Novel elastomer composite blends and methods - ii

ABSTRACT

Elastomer composite blends are produced by novel wet/dry mixing methods and apparatus. In the wet mixing step or stage, fluid streams of particulate filler and elastomer latex are fed to the mixing zone of a coagulum reactor to form a mixture in semi-confined flow continuously from the mixing zone through a coagulum zone to a discharge end of the reactor. The particulate filler fluid is fed under high pressure to the mixing zone, such as to form a jet stream to entrain elastomer latex fluid sufficiently energetically to substantially completely coagulate the elastomer with the particulate filler prior to the discharge end. Highly efficient and effective elastomer coagulation is achieved without the need for a coagulation step involving exposure to acid or salt solution or the like. Novel elastomer composites are produced. Such novel elastomer composites may be cured or uncured, and combine material properties, such as choice of filler, elastomer, level of filler loading, and macro-dispersion, not previously achieved. The coagulum produced by such wet mixing step, with or without intermediate processing steps, is then mixed with additional elastomer in a dry mixing step or stage to form elastomer composite blends. The additional elastomer to the coagulum may be the same as or different from the elastomer(s) used in the wet mixing step.

FIELD OF THE INVENTION

[0001] The present invention is directed to novel methods for producingelastomer composite blends and to novel elastomer composite blendsproduced using such methods. More particularly, the invention isdirected to methods for producing elastomer composite blends havingparticulate filler finely dispersed in elastomer, and to elastomercomposite blends such as curative-free compositions, curative-bearingcompositions, and vulcanized rubber materials and products formed ofsuch compositions.

BACKGROUND

[0002] Numerous products of commercial significance are formed ofelastomeric compositions wherein particulate filler is dispersed in anyof various synthetic elastomers, natural rubber or elastomer blends.Carbon black, for example, is widely used as a reinforcing agent innatural rubber and other elastomers. It is common to produce amasterbatch, that is, a premixture of filler, elastomer and variousoptional additives, such as extender oil, and then in some cases toblend such masterbatch with additional elastomer in a subsequent mixingstep. Carbon black masterbatch is prepared with different grades ofcommercially available carbon black which vary both in surface area perunit weight and in “structure.” Numerous products of commercialsignificance are formed of such elastomeric compositions of carbon blackparticulate filler dispersed in natural rubber. Such products include,for example, vehicle tires wherein different elastomeric compositionsmay be used for the tread portion, sidewalls, wire skim and carcass.Other products include, for example, engine mount bushings, conveyorbelts, windshield wipers and the like. While a wide range of performancecharacteristics can be achieved employing currently available materialsand manufacturing techniques, there has been a long standing need in theindustry to develop elastomeric compositions having improved propertiesand to reduce the cost and complexity of current manufacturingtechniques. In particular, it is known for example that macro-dispersionlevel, that is, the uniformity of dispersion of the carbon black orother filler within the elastomer, can significantly impact performancecharacteristics. For elastomeric compositions prepared by intensivelymixing the carbon black or other filler with natural rubber or otherelastomer (such as in a Banbury mixer or the like), any increase inmacro-dispersion requires longer or more intensive mixing, with theconsequent disadvantages of increased energy costs, manufacturing time,and similar concerns. For carbon black fillers of certain surface areaand structure characteristics, dispersion beyond a certain degree hasnot been possible or commercially practicable using known mixingapparatus and techniques. In addition, such prolonged or more intensivemixing degrades the natural rubber by disruption of the polymeric chainsof the natural rubber elastomer, and so reduces its molecular weight,rendering the finished elastomeric compound undesirable for certainapplications. For use in tire tread, for example, reduced molecularweight is known to cause an undesirable increase in the so-calledrolling resistance of the tire.

[0003] It is well known to employ carbon blacks having higher or lowerstructure and surface area to manipulate the performance characteristicsof an elastomeric composition. Carbon blacks of higher surface area andlower structure are known to improve crack growth resistance andcut-and-chip resistance as well as, generally, abrasion resistance, andother performance qualities. Commercially available mixing techniqueshave been unable to achieve excellent uniformity of dispersion of carbonblacks throughout the elastomer, however, without unacceptabledegradation of the natural rubber. In fact, for typical carbon blackloading levels in natural rubber, such as 45 phr to 75 phr, and oilloading from 0 phr to 10 phr, low structure carbon blacks, such ascarbon blacks of DBPA less than 110 cc/100 g, particularly those havingsurface area above about 45 m²/g to 65 m²/g (CTAB), it has not beenpossible to achieve compounds having less than about 1% undispersedcarbon black (measured as macro-dispersion, as described below)regardless of the duration and intensity level of mixing.

[0004] Furthermore, while theoretical analysis has indicated desirableimprovements in certain performance characteristics of elastomericcompositions employing carbon blacks of higher surface area and lowerstructure, it has not been possible using known physical milling orother mastication processes to obtain such elastomeric compositions inwhich both the molecular weight of the natural rubber is well preservedand satisfactory macro-dispersion levels of the carbon black areachieved. Generally, it has been found, for example, that the elastomerreinforcing properties of a carbon black increase as the particle sizeof the carbon black decreases. However, with extremely fine carbonblacks an anomalous condition is known to be encountered, in which theexpected improvement in properties is not achieved. This is understoodto be due at least in part to the inability of conventional elastomercompounding methods to adequately disperse the carbon black in thenatural rubber without undue breakdown of the elastomer polymer. Therehas been, therefore, consequent inability to take fill advantage of thenatural affinity of the carbon black and the natural rubber for eachother in the case of such carbon blacks.

[0005] Since good dispersion of carbon black in natural rubber compoundshas been recognized for some time as one of the most importantobjectives for achieving good quality and consistent productperformance, considerable effort has been devoted to the development ofprocedures for assessing dispersion quality in rubber. Methods developedinclude, e.g. the Cabot Dispersion Chart and various image analysisprocedures. Dispersion quality can be defined as the state of mixingachieved. An ideal dispersion of carbon black is the state in which thecarbon black agglomerates (or pellets) are broken down into aggregates(accomplished by dispersive mixing) uniformly separated from each other(accomplished by distributive mixing), with the surfaces of all thecarbon black aggregates completely wetted by the rubber matrix (usuallyreferred to as incorporation).

[0006] Common problems in the rubber industry which are often related topoor macro-dispersion can be classified into four major categories:product performance, surface defects, surface appearance and dispersionefficiency. The functional performance and durability of a carbonblack-containing rubber formulation, such as tensile strength, fatiguelife and wear resistance, are affected substantially by macro-dispersionquality. Undispersed carbon black can also cause surface defects onfinished products, including visible defects. Eliminating the presenceof surface defects is of critical importance in molded thin parts forfunctional reasons and in extruded profiles for both aesthetic andfunctional reasons.

[0007] A commercial image analyzer such as the IBAS Compact model imageanalyzer available from Kontron Electronik GmbH (Munich, Germany) can beused to measure macro-dispersion of carbon black or other filler.Typically, in quantitative macro-dispersion tests used in the rubberindustry, the critical cut-off size is 10 microns. Defects larger thanabout 10 microns in size typically consist of undispersed black or otherfiller, as well as any grit or other contaminants, which can affect bothvisual and functional performance. Thus, measuring macro-dispersioninvolves measuring defects on a surface (generated by microtoming,extrusion or cutting) greater than 10 microns in size by total area ofsuch defects per unit area examined using an image analysis procedure.Macro-dispersion D(%) is calculated as follows:${\% \quad {Undispersed}\quad {area}\quad (\%)} = {\frac{1}{A_{m}}{\sum\limits_{i = 1}^{m}{N_{i}\frac{\pi \quad D_{i}^{2}}{4}}}}$

[0008] where

[0009] A_(m)=Total sample surface area examined

[0010] N_(i)=Number of defects with size D_(i)

[0011] D_(i)=Diameter of circle having the same area as that of thedefect (equivalent circle diameter).

[0012] m=number of images

[0013] Macro-dispersion of carbon black or other filler in uncurednatural rubber or other suitable elastomer can be assessed using imageanalysis of cut surface samples. Typically, five to ten arbitrarilyselected optical images are taken of the cut surface for image analysis.Knife marks and the like preferably are removed using a numericalfiltering technique. Cut surface image analysis thus providesinformation regarding the carbon black dispersion quality inside anatural rubber compound. Specifically, percent undispersed area D(%)indicates carbon black macro-dispersion quality. As macro-dispersionquality is degraded, percent undispersed area increases. Dispersionquality can be improved, therefore, by reducing the percent undispersedarea. As noted above, the mixing operations have a direct impact onmixing efficiency and on macro-dispersion. In general, better carbonblack macro-dispersion is achieved in the elastomer, for example in anatural rubber masterbatch, by longer mixing and by more intensivemixing. Unfortunately, however, achieving better macro-dispersion bylonger, more intensive mixing, degrades the elastomer into which thecarbon black is being dispersed. This is especially problematic in thecase of natural rubber, which is highly susceptible tomechanical/thermal degradation. Longer and more intensive mixing, usingknown mixing techniques and apparatus, such as a Banbury mixer, reducesthe molecular weight of the natural rubber masterbatch-composition.Thus, improved macro-dispersion of carbon black in natural rubber isknown to be achieved with a corresponding, generally undesirablereduction in the molecular weight of the rubber.

[0014] In addition to dry mixing techniques, it is known to continuouslyfeed latex and a carbon black slurry to an agitated coagulation tank.Such “wet” techniques are used commonly with synthetic elastomer, suchas SBR. The coagulation tank contains a coagulant such as salt or anaqueous acid solution typically having a pH of about 2.5 to 4. The latexand carbon black slurry are mixed and coagulated in the coagulation tankinto small beads (typically a few millimeters in diameter) referred toas wet crumb. The crumb and acid effluent are separated, typically bymeans of a vibrating shaker screen or the like. The crumb is then dumpedinto a second agitated tank where it is washed to achieve a neutral ornear neutral pH. Thereafter the crumb is subjected to additionalvibrating screen and drying steps and the like. Variations on thismethod have been suggested for the coagulation of natural and syntheticelastomers. In U.S. Pat. No. 4,029,633 to Hagopian et al, which like thepresent invention is assigned to Cabot Corporation, a continuous processfor the preparation of elastomer masterbatch is described. An aqueousslurry of carbon black is prepared and mixed with a natural or syntheticelastomer latex. This mixture undergoes a so-called creaming operation,optionally using any of various known creaming agents. Following thecreaming of the carbon black/latex mixture, it is subjected to acoagulation step. Specifically, the creamed carbon black/latex mixtureis introduced as a single coherent stream into the core of a stream ofcoagulating liquor. The solid stream of creamed carbon black/latexmixture is said to undergo shearing and atomizing by the stream ofcoagulating liquor prior to coagulation, being then passed to a suitablereaction zone for completion of the coagulation. Following suchcoagulation step, the remainder of the process is substantiallyconventional, involving separation of the crumb from the waste product“serum” and washing and drying of the crumb. A somewhat similar processis described in U.S. Pat. No. 3,048,559 to Heller et al. An aqueousslurry of carbon black is continuously blended with a stream of naturalor synthetic elastomer or latex. The two streams are mixed underconditions described as involving violent hydraulic turbulence andimpact. As in the case of the Hagopian et al patent mentioned above, thecombined stream of carbon black slurry and elastomer latex issubsequently coagulated by the addition of an acid or salt coagulantsolution.

[0015] There has long been a need in various industries for elastomericcompounds of particulate filler dispersed in suitable elastomer havingimproved macro-dispersion, especially, for example, carbon blackdispersed in natural rubber blended with another elastomer. As discussedabove, improved macro-dispersion can provide correspondingly improvedaesthetic and functional characteristics. Especially desirable are newelastomeric compounds of carbon black in a blend of natural rubber andsynthetic elastomer, wherein improved macro-dispersion is achievedtogether with higher molecular weight of the natural rubber. It is anobject of the present invention to meet some or all of these long feltneeds.

SUMMARY OF THE INVENTION

[0016] In accordance with a first aspect, a method for preparingelastomer composite blends comprises first preparing elastomermasterbatch by feeding simultaneously a particulate filler fluid and anelastomer latex fluid to a mixing zone of a coagulum reactor.Preferably, the coagulum reactor has an elongate coagulum zone extendsfrom the mixing zone, most preferably having a progressively increasingcross-sectional area in the downstream direction toward a discharge endof the coagulum reactor. The elastomer latex may be either natural orsynthetic and the particulate filler fluid comprises carbon black orother particulate filler effective to coagulate the latex. Theparticulate filler fluid is fed to the mixing zone preferably as acontinuous, high velocity jet of injected fluid, while the latex fluidis fed at low velocity. The velocity, flow rate and particulateconcentration of the particulate filler fluid are sufficient to causemixture with high shear of the latex fluid and flow turbulence of themixture within at least an upstream portion of the coagulum zone so asto substantially completely coagulate the elastomer latex with theparticulate filler prior to the discharge end. Substantially completecoagulation can thus be achieved, in accordance with preferredembodiments, without the need of employing an acid or salt coagulationagent. The coagulated product of such wet mixing step then is dry mixedwith additional elastomer to form an elastomer composite blend. Suchadditional elastomer may be the same as, or different from, theelastomer used in the wet mixing step. Optionally, additional filler canbe added during the dry mixing step. Such additional filler can be thesame as, or different from, the particulate filler used in the wetmixing step.

[0017] In accordance with yet another aspect, elastomer composite blendsare provided as a product of the process disclosed here. In accordancewith preferred embodiments, novel elastomer composite blends areprovided having macro-dispersion level of the particulate filler,molecular weight of the elastomer, particulate loading level, choice ofparticulate filler (including, for example, carbon black fillers ofexceptionally high surface area and low structure) and/or othercharacteristics not previously achieved. In that regard, preferredelastomer composite blends disclosed here have excellentmacro-dispersion, even of certain fillers, such as carbon blacks havinga structure to surface area ratio DBP:CTAB less than 1.2 and even lessthan 1, in elastomers such as natural rubber, etc. with little or nodegradation of the molecular weight of the elastomer. In accordance withyet other aspects of the invention, intermediate products are providedas well as final products which are formed of the elastomer compositeblends produced by the method disclosed here. Macro-dispersion heremeans the macro-dispersion D(%) of the particulate filler measured aspercent undispersed area for defects larger than 10 microns. Inelastomer composite blends disclosed here comprising natural rubber, themolecular weight of the natural rubber, that is, the MW_(sol) (weightaverage) of the sol portion, preferably is at least about 300,000, morepreferably at least about 400,000, being in certain preferredembodiments between 400,000 and 900,000. The elastomer composite blendsoptionally comprise extender oil, such as about 0 to 20 phr, morepreferably about 0 to 10 phr extender oil, and/or other ingredients suchas are well known for optional use in compounding natural rubber and/orother elastomers with carbon black and/or other fillers. As discussedfurther below in connection with certain preferred and exemplaryembodiments, the novel elastomer composite blends disclosed here canprovide highly desirable physical properties and performancecharacteristics. Accordingly, the invention presents a significanttechnological advance.

[0018] These and other aspects and advantages of various embodiments ofthe invention will be further understood in view of the followingdetailed discussion of certain preferred embodiments.

BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The following discussion of certain preferred embodiments willmake reference to the appended drawings wherein:

[0020]FIG. 1 is a schematic flow chart illustration of the apparatus andmethod for preparing elastomer masterbatch in accordance with certainpreferred embodiments;

[0021]FIG. 2 is an elevation view, partly schematic, of a preferredembodiment consistent with the schematic flow chart illustration of FIG.1;

[0022]FIG. 3 is an elevation view, partially schematic, of analternative preferred embodiment consistent with the schematic flowchart illustration of FIG. 1;

[0023]FIG. 4 is an elevation view, partially in section, of the mixhead/coagulum reactor assembly of the embodiment of FIG. 3;

[0024]FIG. 5 is an elevation view, partially in section, correspondingto the view of FIG. 4, illustrating an alternative preferred embodiment;

[0025]FIG. 6 is a section view taken through line 6-6 of FIG. 5;

[0026]FIG. 7 is a section view of a mix head suitable for use in analternative preferred embodiment;

[0027]FIG. 8 is a graph showing the surface area and structureproperties (CTAB and DBPA) of carbon blacks employed in certain highlypreferred masterbatch compositions in accordance with the presentinvention;

[0028] FIGS. 9-25 are graphs showing the macro-dispersion, naturalrubber molecular weight and/or other characteristics of novel elastomercomposites in accordance with this invention comprising carbon blacksshown in FIG. 8, in some cases along with data relating to controlsamples for comparison, exemplifying the significant improvements inphysical characteristics and performance properties achieved by theelastomer composites;

[0029] FIGS. 26-29 are graphs showing morphological properties of carbonblacks, i.e., structure (DBPA) and surface area (CTAB), and identifyingregions or zones of carbon blacks (by such morphological properties)which are suitable for specific product applications; and

[0030]FIGS. 30 and 31 are graphs showing the macro-dispersion andnatural rubber molecular weight of novel elastomer composites inaccordance with this invention, along with control samples forcomparison.

[0031] It should be understood that the appended drawings are notnecessarily precisely to scale. Certain features may have been enlargedor reduced for convenience or clarity of illustration. Directionalreferences used in the following discussion are based on the orientationof components illustrated in the drawings unless otherwise stated orotherwise clear from the context. In general, apparatus in accordancewith. different embodiments of the invention can be employed in variousarrangements. It will be within the ability of those skilled in the art,given the benefit of the present disclosure, to determine appropriatedimensions and orientations for apparatus of the invention employingroutine technical skills and taking into account well-known factorsparticular to the intended application, such as desired productionvolumes, material selection, duty cycle, and the like. Reference numbersused in one drawing may be used in other drawings for the same featureor element.

DETAILED DESCRIPTION OF CERTAIN PREFERRED EMBODIMENTS

[0032] By virtue of the method and apparatus disclosed here, elastomercomposite blends are produced, comprising (i) elastomer masterbatchproduced in a continuous flow process involving mixture of elastomerlatex and particulate filler fluids at turbulence levels and flowcontrol conditions sufficient to achieve coagulation even without use oftraditional coagulating agents, and (ii) additional elastomer added tosuch elastomer masterbatch in a dry mixing step. In fact, it will beimmediately recognized to be of great commercial benefit: (A) thatelastomer masterbatch crumb is achieved, that is, coagulated latex isachieved in accordance with the “wet mixing” step of the present method,without the need for either intensive dry mastication of elastomer withfiller or exposing a liquid latex/particulate composition to a stream ortank of coagulant, and (B) that elastomer composite blend is thenachieved by the “dry mixing” step involving dry mixing such masterbatchwith additional elastomer. Thus, in routine commercial implementationthe cost and complexity of employing acid coagulation solutions can beavoided. Prior techniques involving premixing of latex and particulate,such as in the above-mentioned Heller et al patent and Hagopian et alpatent do not even recognize the possibility of achieving coagulationwithout exposing the latex/particulate mixture to the usual coagulantsolution with its attendant cost and waste disposal disadvantages.

[0033] Advantageous flexibility is achieved by the wet/dry mixing methoddisclosed here for making elastomer composite blend. In particular,flexibility is provided as to the choice of elastomer(s) employed in thefluid or “wet mixing” step and in the choice of elastomer(s) used in thesubsequent “dry mixing” step. The same elastomer (or mixture ofelastomers) can be used in the wet and dry mixing steps or,alternatively, different elastomers can be used in any suitable relativeweight proportion. Further flexibility is provided in that additionalfiller may optionally be added during the dry mix step. Such additionalfiller can be the same as or different from the particulate filler usedin the wet mixing step. Advantageously, in preferred embodiments of themethod disclosed here, the excellent macro-dispersion of particulatefiller achieved in the elastomer masterbatch produced by the wet mixingstep is maintained or even further improved in the subsequent dry mixingstep. Without wishing to be bound by theory, it presently is understoodthat, at least in certain preferred embodiments, a multi-phase elastomercomposite blend is produced by the wet/dry method disclosed here. Thatis, although difficult to identify or observe using techniques currentlyin general use in the elastomer industry, the elastomer composite blendis understood to comprise at lease one elastomer phase produced duringthe wet mixing step and a subsequent elastomer phase produced during thedry mixing step. The degree of intermingling of the two phases and thedegree to which boundary layers between the two phases are more or lessdistinct will depend on numerous factors including, for example, themutual affinity of the elastomer of the wet mixing step and that of thedry mixing step, the level of particulate loading, the choice ofparticulate filler(s) and whether additional filler was added during thedry mixing step, the relative weight proportion of the wet mixing stepelastomer and the dry mixing step elastomer, etc.

[0034] The advantageous flexibility afforded by the present invention,and its use to better control distribution of filler between twodifferent elastomer phases in an elastomer composite blend is seen inthe example of an elastomer composite blend comprising natural rubber,butadiene rubber (referred in this discussion, in some instances, as“BR”) and carbon black filler. For certain applications it is preferredto have the carbon black filler primarily in the natural rubber phase ofthe elastomer composite blend. In accordance with prior known dry/drymixing techniques, the carbon black can be mixed with the natural rubberusing a dry mixing technique, followed by the addition and further drymixing of BR. A disadvantageously large portion of the carbon black willmigrate into the BR phase, due to its affinity for the BR phase and theless than desirable macro-dispersion of the carbon black in the naturalrubber phase. In comparison, improved performance properties ofcomparable elastomer composite blends prepared by the wet/dry mixingmethod disclosed here indicate that more of the carbon black is retainedin the natural rubber phase when the carbon black is mixed with thenatural rubber in the initial wet mixing step, followed by the additionof BR in a subsequent dry mixing step.

[0035] In accordance with the wet mixing step of the method disclosedhere, feed rates of latex fluid and particulate filler fluid to themixing zone of the coagulum reactor can be precisely metered to achievehigh yield rates, with little free latex and little undispersed fillerin the product crumb at the discharge end of the coagulum reactor.Without wishing to be bound by theory, it presently is understood that aquasi-mono-phase system is established in the mixing zone except thatcoagulum solids are being formed there and/or downstream thereof in thecoagulum zone. Extremely high feed velocity of the particulate fillerfluid into the mixing zone of the coagulum reactor and velocitydifferential relative the latex fluid feed are believed to besignificant in achieving sufficient turbulence, i.e., sufficientlyenergetic shear of the latex by the impact of the particulate fillerfluid jet for thorough mixing and dispersion of the particulate into thelatex fluid and coagulation. High mixing energies yield productmasterbatch crumb with excellent dispersion, together with controlledproduct delivery. The coagulum is created and then formed into adesirable extrudate. The particulate filler fluid and elastomer latexare fed preferably continuously, meaning that an ongoing flow ofcoagulated masterbatch is established from the mixing zone to thedischarged end of the coagulum reactor while an uninterrupted flow ofthe feed fluids is maintained. Typically, the uninterrupted flow of thefeed fluids and simultaneous discharge of coagulated masterbatch aremaintained for one or more hours, preferably, for example, more than 24hours, and ever perhaps for a week or more.

[0036] Certain preferred embodiments are discussed below, of methods andapparatus for producing the novel elastomer composite blends disclosedhere. While various preferred embodiments of the invention can employ avariety of different fillers and elastomers, certain portions of thefollowing detailed description of method and apparatus aspects of theinvention will, in some instances, for convenience, describe masterbatchcomprising natural rubber and carbon black. It will be within theability of those skilled in the art, given the benefit of thisdisclosure, to employ the method and apparatus disclosed here inaccordance with the principles of operation discussed here to producemasterbatch and elastomer composite blends comprising a number ofalternative or additional elastomers, fillers and other materials. Inbrief, preferred methods for preparing elastomer masterbatch involvefeeding simultaneously a slurry of carbon black or other filler and anatural rubber latex fluid or other suitable elastomer fluid to a mixingzone of a coagulum reactor. A coagulum zone extends from the mixingzone, preferably progressively increasing in cross-sectional area in thedownstream direction from an entry end to a discharge end. The slurry isfed to the mixing zone preferably as a continuous, high velocity jet ofinjected fluid, while the natural rubber latex fluid is fed atrelatively low velocity. The high velocity, flow rate and particulateconcentration of the filler slurry are sufficient to cause mixture andhigh shear of the latex fluid, flow turbulence of the mixture within atleast an upstream portion of the coagulum zone, and substantiallycompletely coagulate the elastomer latex prior to the discharge end.Substantially complete coagulation can thus be achieved, in accordancewith preferred embodiments, without the need of employing an acid orsalt coagulation agent. The preferred continuous flow method ofproducing the elastomer composites comprises the continuous andsimultaneous feeding of the latex fluid and filler slurry to the mixingzone of the coagulum reactor, establishing a continuous, semi-confinedflow of a mixture of the latex and filler slurry in the coagulum zone.Elastomer composite crumb in the form of “worms” or globules aredischarged from the discharge end of the coagulum reactor as asubstantially constant flow concurrently with the on-going feeding ofthe latex and carbon black slurry streams into the mixing zone of thecoagulum reactor. Notably, the plug-type flow and atmospheric or nearatmospheric pressure conditions at the discharge end of the coagulumreactor are highly advantageous in facilitating control and collectionof the elastomer composite product, such as for immediate or subsequentfurther processing steps. Feed rates of the natural rubber latex fluidand carbon black slurry to the mixing zone of the coagulum reactor canbe precisely metered to achieve high yield rates, with little free latexand little undispersed carbon black in the product crumb at thedischarge end of the coagulum reactor. Without wishing to be bound bytheory, it presently is understood that a quasi-mono-phase system isestablished in the mixing zone except that coagulum solids are beingformed there and/or downstream thereof in the coagulum zone. Extremelyhigh feed velocity of the carbon black slurry into the mixing zone ofthe coagulum reactor and velocity differential relative the naturalrubber latex fluid feed are believed to be significant in achievingsufficient turbulence, i.e., sufficiently energetic shear of the latexby the impact of the particulate filler fluid jet for thorough mixingand dispersion of the particulate into the latex fluid and coagulation.High mixing energies yield the novel product with excellentmacro-dispersion, together with controlled product delivery. Thecoagulum is created and then formed into a desirable extrudate.

[0037] The elastomer composite prepared by the above-described wetmixing technique and apparatus is formed into elastomer composite blendsof the invention by subsequent dry mixing with additional elastomer.Thus, the present invention can be described as involving a wet/drymethod, whereas prior-known techniques employed a dry/dry method inwhich a masterbatch first is formed by dry mixing and additionalelastomer is added by further dry mixing. The dry mixing step of thewet/dry mixing method of the present invention can be carried out withcommercially available apparatus and techniques including, for example,Banbury mixers and the like. The additional elastomer added during thedry mixing step of the wet/dry mixing method disclosed here can be oneor more elastomers which are the same as or different from theelastomer(s) employed to form the masterbatch. Other ingredients alsomay be added along with the additional elastomer during the dry mix stepincluding, for example, extender oil, additional particulate filler,curatives, etc., in those embodiments wherein additional particulatefiller is added during the dry mixing step such additional filler can bethe same as or different from the filler(s) used in the masterbatchformed by the wet mixing step.

[0038] The aforesaid preferred apparatus and techniques for producingthe elastomer composite blends disclosed here are discussed inconjunction with the appended drawings, wherein a continuous flow wetmixing step for producing elastomer masterbatch employs a continuous,semi-confined flow of elastomer latex, for example, natural rubber latex(field latex or concentrate) mixed with a filler slurry, for example, anaqueous slurry of carbon black, in a coagulum reactor forming anelongate coagulum zone which extends, preferably with progressivelyincreasing cross-sectional area, from an entry end to a discharge end.The term “semi-confined” flow refers to a highly advantageous feature.As used here the term is intended to mean that the flow path followed bythe mixed latex fluid and filler slurry within the coagulum reactor isclosed or substantially closed upstream of the mixing zone and is openat the opposite, downstream end of the coagulum reactor, that is, at thedischarge end of the coagulum reactor. Turbulence conditions in theupstream portion of the coagulum zone are maintained in on-going, atleast quasi-steady state fashion concurrently with substantially plugflow-type conditions at the open discharge end of the coagulum reactor.The discharge end is “open” at least in the sense that it permitsdischarge of coagulum, generally at or near atmospheric pressure and,typically, by simple gravity drop (optionally within a shrouded orscreened flow path) into suitable collection means, such as the feedhopper of a de-watering extruder. Thus, the semi-confined flow resultsin a turbulence gradient extending axially or longitudinally within atleast a portion of the coagulum reactor. Without wishing to be bound bytheory, it presently is understood that the coagulum zone is significantin permitting high turbulence mixing and coagulation in an upstreamportion of the coagulum reactor, together with substantially plug-typedischarge flow of a solid product at the discharge end. Injection of thecarbon black or other filler slurry as a continuous jet into the mixingzone occurs in on-going fashion simultaneously, with ease of collectionof the elastomer masterbatch crumb discharged under substantiallyplug-type flow conditions and generally ambient pressure at thedischarge end of the coagulum reactor. Similarly, axial velocities ofthe slurry through the slurry nozzle into the mixing zone and,typically, at the upstream end of the coagulum zone are substantiallyhigher than at the discharge end. Axial velocity of the slurry willtypically be several hundred feet per second as it enters the mixingzone, preferably from a small bore, axially oriented feed tube inaccordance with preferred embodiments discussed below. The axialvelocity of the resultant flow at the entry end of a coagulum reactorwith expanding cross-sectional area in a typical application may be, forexample, 5 to 20 feet per second, and more usually 7 to 15 feet persecond. At the discharge end, in contrast again, axial velocity of themasterbatch crumb product being discharged there will in a typicalapplication be approximately 1 to 10 feet per second, and more generally2 to 5 feet per second. Thus, the aforesaid semi-confined turbulent flowachieves the highly significant advantage that natural rubber or otherelastomer latex is coagulated by mixture with carbon black or otherfiller even in the absence of subsequent treatment in a stream or tankof acid, salt or other coagulant solution, with controlled, preferablyquasi-molded product delivery from the coagulum reactor for subsequentprocessing.

[0039] It should be understood in this regard that reference to thecoagulum reactor as being “open” at the discharge end is not intended tomean that the discharge end is necessarily exposed to view or easilyaccessed by hand. It may instead be permanently or releasably attachedto a collection device or subsequent processing device, such as adiverter (discussed further below), dryer, etc. The discharge end of thecoagulum reactor is open in the important sense that the turbulent flowwithin the coagulum zone of the coagulum reactor, which is under highpressure and sealed against any significant rearward (i.e., upstream)travel at the mixing zone, is permitted to establish the aforesaidpressure and/or velocity gradient as it travels toward and exits fromthe discharge end.

[0040] It should also be recognized in this regard that the turbulenceof the flow lessens along the coagulum reactor toward the discharge end.Substantial plug flow of a solid product is achieved prior to thedischarge end, dependent upon such factors as percent of capacityutilization, selection of materials and the like. Reference here to theflow being substantially plug flow at or before the discharge end of thecoagulum reactor should be understood in light of the fact that the flowat the discharge end is composed primarily or entirely of masterbatchcrumb, that is, globules or “worms” of coagulated elastomer masterbatch.The crumb is typically quasi-molded to the inside shape of the coagulumzone at the point along the coagulum zone at which flow becamesubstantially plug flow. The ever-advancing mass of “worms” or globulesadvantageously have plug-type flow in the sense that they are travelinggenerally or primarily axially toward the discharge end and at any pointin time in a given cross-section of the coagulum zone near the dischargeend have a fairly uniform velocity, such that they are readily collectedand controlled for further processing. Thus, the fluid phase mixingaspect disclosed here can advantageously be carried out at steady stateor quasi-steady state conditions, resulting in high levels of productuniformity.

[0041] A preferred embodiment of the wet mixing step of the method andapparatus disclosed here is illustrated schematically in FIG. 1. Thoseskilled in the art will recognize that the various aspects of systemconfiguration, component selection and the like will depend to someextent on the particular characteristics of the intended application.Thus, for example, such factors as maximum system through-put capacityand material selection flexibility will influence the size and layout ofsystem components. In general, such considerations will be well withinthe ability of those skilled in the art given the benefit of the presentdisclosure. The system illustrated in FIG. 1 is seen to include meansfor feeding natural rubber latex or other elastomer latex fluid at lowpressure and low velocity continuously to a mixing zone of a coagulumreactor. More particularly, a latex pressure tank 10 is shown, to holdthe feed supply of latex under pressure. Alternatively, a latex storagetank can be used, equipped with a peristaltic pump or series of pumps orother suitable feed means adapted to hold elastomer latex fluid to befed via feed line 12 to a mixing zone of a coagulum reactor 14. Latexfluid in tank 10 may be held under air or nitrogen pressure or the like,such that the latex fluid is fed to the mixing zone at a line pressureof preferably less than 10 psig, more preferably about 2-8 psig, andtypically about 5 psig. The latex feed pressure and the flow lines,connections, etc., of the latex feed means should be arranged to causeshear in the flowing latex fluid as low as reasonably possible.Preferably all flow lines, for example, are smooth, with only largeradius turns, if any, and smooth or faired line-to-lineinterconnections. The pressure is selected to yield the desired flowvelocity into the mixing zone; an example of a useful flow velocity isno more than about 12 feet per second.

[0042] Suitable elastomer latex fluids include both natural andsynthetic elastomer latices and latex blends. The latex must, of course,be suitable for coagulation by the selected particulate filler and mustbe suitable for the intended purpose or application of the final rubberproduct. It will be within the ability of those skilled in the art toselect suitable elastomer latex or a suitable blend of elastomer laticesfor use in the methods and apparatus disclosed here, given the benefitof this disclosure. Exemplary elastomers include, but are not limitedto, rubbers, polymers (e.g., homopolymers, copolymers and/orterpolymers) of 1,3-butadiene, styrene, isoprene, isobutylene,2,3-dimethyl-1,3-butadiene, acrylonitrile, ethylene, and propylene andthe like. The elastomer may have a glass transition temperature (Tg) asmeasured by differential scanning calorimetry (DSC) ranging from about−120° C. to about 0° C. Examples include, but are not limited to,styrene-butadiene rubber (SBR), natural rubber and its derivatives suchas chlorinated rubber, polybutadiene, polyisoprene,poly(stryene-co-butadiene) and the oil extended derivatives of any ofthem. Blends of any of the foregoing may also be used. The latex may bein an aqueous carrier liquid. Alternatively, the liquid carrier may be ahydrocarbon solvent. In any event, the elastomer latex fluid must besuitable for controlled continuous feed at appropriate velocity,pressure and concentration into the mixing zone. Particular suitablesynthetic rubbers include: copolymers of from about 10 to about 70percent by weight of styrene and from about 90 to about 30 percent byweight of butadiene such as copolymer of 19 parts styrene and 81 partsbutadiene, a copolymer of 30 parts styrene and 70 parts butadiene, acopolymer of 43 parts styrene and 57 parts butadiene and a copolymer of50 parts styrene and 50 parts butadiene; polymers and copolymers ofconjugated dienes such as polybutadiene, polyisoprene, polychloroprene,and the like, and copolymers of such conjugated dienes with an ethylenicgroup-containing monomer copolymerizable therewith such as styrene,methyl styrene, chlorostyrene, acrylonitrile, 2-vinyl-pyridine,5-methyl-2-vinylpyridine, 5-ethyl-2-vinylpyridine,2-methyl-5-vinylpyridine, alkyl-substituted acrylates, vinyl ketone,methyl isopropenyl ketone, methyl vinyl either, alphamethylenecarboxylic acids and the esters and amides thereof such as acrylic acidand dialkylacrylic acid amide. Also suitable for use herein arecopolymers of ethylene and other high alpha olefins such as propylene,butene-1 and pentene-1.

[0043] The additional elastomer added during the dry mixing step of thewet/dry mixing method disclosed here can employ any elastomer or mixtureof elastomers suitable to the intended use or application, includingthose listed above for use in the wet mixing step. In accordance withcertain preferred embodiments, the elastomer latex employed in the wetmixing step is natural rubber latex and the additional elastomeremployed in the dry mixing step is butadiene rubber (BR). In suchpreferred embodiments, the butadiene rubber preferably forms the minorphase or constituent of the elastomer composite blend, most preferablybeing from 10% to 50% by weight of total elastomer in the elastomercomposite blend. In accordance with certain other preferred embodiments,the elastomer latex employed in the wet mixing step is natural rubberlatex and the additional elastomer employed in the dry mixing step isstyrene-butadiene rubber (SBR). In such preferred embodiments, the SBRpreferably forms the major phase or constituent of the elastomercomposite blend, most preferably being from 50% to 90% by weight oftotal elastomer in the elastomer composite blend. In accordance withcertain other preferred embodiments, the additional elastomer is naturalrubber. In accordance with certain other preferred embodiments, theelastomer latex employed in the wet mixing step is butadiene rubberlatex and the additional elastomer employed in the dry mixing step isSBR. In such preferred embodiments, the SBR preferably from 10% to 90%by weight of total elastomer in the elastomer composite blend. Inaccordance with certain other preferred embodiments, the elastomer latexemployed in the wet mixing step is butadiene rubber latex and theadditional elastomer employed in the dry mixing step is natural rubber.In such preferred embodiments, the natural rubber preferably is theminor constituent or phase of the elastomer composite blend, mostpreferably being from 10% to 50% by weight of total elastomer in theelastomer composite blend. In accordance with certain other preferredembodiments employing butadiene rubber latex in the wet mixing step, theadditional elastomer is additional butadiene rubber. In accordance withcertain other preferred embodiments, the elastomer latex employed in thewet mixing step is SBR and the additional elastomer is butadiene rubber.In such preferred embodiments, the butadiene rubber preferably is from10% to 90% by weight of total elastomer in the elastomer compositeblend. In accordance with certain other preferred embodiments, theelastomer latex employed in the wet mixing step is SBR and theadditional elastomer is natural rubber. In such preferred embodiments,the natural rubber preferably is the major constituent or phase, mostpreferably being from 50% to 90% by weight of total elastomer in theelastomer composite blend. Certain other preferred embodiments SBR isemployed in both the wet mixing and dry mixing steps, thus beingessentially 100% of the elastomer in the elastomer composite blend.

[0044] As noted further below, the rubber compositions of the presentinvention can contain, in addition to the elastomer and filler, curingagents, a coupling agent, and optionally, various processing aids, oilextenders and antidegradents. In that regard, it should be understoodthat the elastomer composite blends disclosed here include vulcanizedcompositions (VR), thermoplastic vulcanizates (TPV), thermoplasticelastomers (TPE) and thermoplastic polyolefms (TPO). TPV, TPE, and TPOmaterials are further classified by their ability to be extruded andmolded several times without substantial loss of performancecharacteristics. Thus, in making the elastomer composite blends one ormore curing agents such as, for example, sulfur, sulfur donors,activators, accelerators, peroxides, and other systems used to effectvulcanization of the elastomer composition may be used.

[0045] Where the elastomer latex employed in the wet mixing stepcomprises natural rubber latex, the natural rubber latex can comprisefield latex or latex concentrate (produced, for example, by evaporation,centrifugation or creaming). The natural rubber latex must, of course,be suitable for coagulation by the carbon black. The latex is providedtypically in an aqueous carrier liquid. Alternatively, the liquidcarrier may be a hydrocarbon solvent. In any event, the natural rubberlatex fluid must be suitable for controlled continuous feed atappropriate velocity, pressure and concentration into the mixing zone.The well known instability of natural rubber latex is advantageouslyaccommodated, in that it is subjected to relatively low pressure and lowshear throughout the system until it is entrained into the aforesaidsemi-confined turbulent flow upon encountering the extraordinarily highvelocity and kinetic energy of the carbon black slurry in the mixingzone. In certain preferred embodiments, for example, the natural rubberis fed to the mixing zone at a pressure of about 5 psig, at a feedvelocity in the range of about 3-12 ft. per second, more preferablyabout 4-6 ft. per second. Selection of a suitable latex or blend oflatices will be well within the ability of those skilled in the artgiven the benefit of the present disclosure and the knowledge ofselection criteria generally well recognized in the industry. Theparticulate filler fluid, for example, carbon black slurry, is fed tothe mixing zone at the entry end of coagulum reactor 14 via feed line16. The slurry may comprise any suitable filler in a suitable carrierfluid. Selection of the carrier fluid will depend largely upon thechoice of particulate filler and upon system parameters. Both aqueousand non-aqueous liquids may be used, with water being preferred in manyembodiments in view of its cost, availability and suitability of use inthe production of carbon black and certain other filler slurries.

[0046] When a carbon black filler is used, selection of the carbon blackwill depend largely upon the intended use of the elastomer compositeblend. Optionally, the carbon black filler can include also any materialwhich can be slurried and fed to the mixing zone in accordance with theprinciples disclosed here. Suitable additional particulate fillersinclude, for example, conductive fillers, reinforcing fillers, fillerscomprising short fibers (typically having an L/D aspect ratio less than40), flakes, etc. Thus, exemplary particulate fillers which can beemployed in producing elastomer masterbatch in accordance with themethods and apparatus disclosed here, are carbon black, fumed silica,precipitated silica, coated carbon black, chemically functionalizedcarbon blacks, such as those having attached organic groups, andsilicon-treated carbon black, either alone or in combination with eachother. Suitable chemically functionalized carbon blacks include thosedisclosed in International Application No. PCT/US95/16194 (WO9618688),the disclosure of which is hereby incorporated by reference. Insilicon-treated carbon black, a silicon containing species such as anoxide or carbide of silicon, is distributed through at least a portionof the carbon black aggregate as an intrinsic part of the carbon black.Conventional carbon blacks exist in the form of aggregates, with eachaggregate consisting of a single phase, which is carbon. This phase mayexist in the form of a graphitic crystallite and/or amorphous carbon,and is usually a mixture of the two forms. As discussed elsewhereherein, carbon black aggregates may be modified by depositingsilicon-containing species, such as silica, on at least a portion of thesurface of the carbon black aggregates. The result may be described assilicon-coated carbon blacks. The materials described herein assilicon-treated carbon blacks are not carbon black aggregates which havebeen coated or otherwise modified, but actually represent a differentkind of aggregate. In the silicon-treated carbon blacks, the aggregatescontain two phases. One phase is carbon, which will still be present asgraphitic crystallite and/or amorphous carbon, while the second phase issilica (and possibly other silicon-containing species). Thus, thesilicon-containing species phase of the silicon-treated carbon black isan intrinsic part of the aggregate; it is distributed throughout atleast a portion of the aggregate. It will be appreciated that themultiphase aggregates are quite different from the silica-coated carbonblacks mentioned above, which consist of pre-formed, single phase carbonblack aggregates having silicon-containing species deposited on theirsurface. Such carbon blacks may be surface-treated in order to place asilica functionality on the surface of the carbon black aggregate. Inthis process, an existing aggregate is treated so as to deposit or coatsilica (as well as possibly other silicon-containing species) on atleast a portion of the surface of the aggregate. For example, an aqueoussodium silicate solution may be used to deposit amorphous silica on thesurface of carbon black aggregates in an aqueous slurry at high pH, suchas 6 or higher, as discussed in Japanese Unexamined Laid-Open (Kokai)Publication No. 63-63755. More specifically, carbon black may bedispersed in water to obtain an aqueous slurry consisting, for example,of about 5% by weight carbon black and 95% by weight water. The slurryis heated to above about 70° C., such as to 85-95° C., and the pHadjusted to above 6, such as to a range of 10-11, with an alkalisolution. A separate preparation is made of sodium silicate solution,containing the amount of silica which is desired to be deposited on thecarbon black, and an acid solution to bring the sodium silicate solutionto a neutral pH. The sodium silicate and acid solutions are addeddropwise to the slurry, which is maintained at its starting pH valuewith acid or alkali solution as appropriate. The temperature of thesolution is also maintained. A suggested rate for addition of the sodiumsilicate solution is to calibrate the dropwise addition to add about 3weight percent silicic acid, with respect to the total amount of carbonblack, per hour. The slurry should be stirred during the addition, andafter its completion for from several minutes (such as 30) to a fewhours (i.e., 2-3). In contrast, silicon-treated carbon blacks may beobtained by manufacturing carbon black in the presence of volatizablesilicon-containing compounds. Such carbon blacks are preferably producedin a modular or “staged” furnace carbon black reactor having acombustion zone followed by a zone of converging diameter, a feed stockinjection zone with restricted diameter, and a reaction zone. A quenchzone is located downstream of the reaction zone. Typically, a quenchingfluid, generally water, is sprayed into the stream of newly formedcarbon black particles flowing from the reaction zone. In producingsilicon-treated carbon black, the aforesaid volatizablesilicon-containing compound is introduced into the carbon black reactorat a point upstream of the quench zone. Useful compounds are volatizablecompounds at carbon black reactor temperatures. Examples include, butare not limited to, silicates such as tetraethoxy orthosilicate (TEDS)and tetramethoxy orthosilicate, silanes such as, tetrachloro silane, andtrichloro methylsilane; and colatile silicone polymers such asoctamethylcyclotetrasiloxane (OMTS). The flow rate of the volatilizablecompound will determine the weight percent of silicon in the treatedcarbon black. The weight percent of silicon in the treated carbon blacktypically ranges from about 0.1 percent to 25 percent, preferably about0.5 percent to about 10 percent, and more preferably about 2 percent toabout 6 percent. The volatizable compound may be pre-mixed with thecarbon black-forming feed stock and introduced with the feed stock intothe reaction zone. Alternatively, the volatizable compound may beintroduced to the reaction zone separately, either upstream ordownstream from the feed stock injection point.

[0047] As noted above, additives may be used, and in this regardcoupling agents useful for coupling silica or carbon black should beexpected to be useful with the silicon-treated carbon blacks. Carbonblacks and numerous additional suitable particulate fillers arecommercially available and are known to those skilled in the art.

[0048] Selection of the particulate filler or mixture of particulatefillers will depend largely upon the intended use of the elastomercomposite blends. As used here, particulate filler can include anymaterial which can be slurried and fed to the mixing zone in accordancewith the principles disclosed here. Suitable particulate fillersinclude, for example, conductive fillers, reinforcing fillers, fillerscomprising short fibers (typically having an L/D aspect ratio less than40), flakes, etc. In addition to the carbon black and silica-typefillers mentioned above, fillers can be formed of clay, glass, polymer,such as aramid fiber, etc. It will be within the ability of thoseskilled in the art to select suitable particulate fillers for use in themethod and apparatus disclosed here given the benefit of the presentdisclosure, and it is expected that any filler suitable for use inelastomer compositions may be incorporated into the elastomer compositesusing the teachings of the present disclosure. Of course, blends of thevarious particulate fillers discussed herein may also be used Preferredembodiments of the invention consistent with FIG. 1 are especially welladapted to preparation of particulate filler fluid comprising aqueousslurries of carbon black. In accordance with known principles, it willbe understood that carbon blacks having lower surface area per unitweight must be used in higher concentration in the particulate slurry toachieve the same coagulation efficacy as lower concentrations of carbonblack having higher surface area per unit weight. Agitated mixing tank18 receives water and carbon black, e.g., optionally pelletized carbonblack, to prepare an initial mixture fluid. Such mixture fluid passesthrough discharge port 20 into fluid line 22 equipped with pumping means24, such as a diaphragm pump or the like. Line 28 passes the mixturefluid to colloid mill 32, or alternatively a pipeline grinder or thelike, through intake port 30. The carbon black is dispersed in theaqueous carrier liquid to form a dispersion fluid which is passedthrough outlet port 31 and fluid line 33 to a homogenizer 34. Pumpingmeans 36, preferably comprising a progressing cavity pump or the like isprovided in line 33. Homogenizer 34 more finely disperses the carbonblack in the carrier liquid to form the carbon black slurry which is fedto the mixing zone of the coagulum reactor 14. It has an inlet port 37in fluid communication with line 33 from the colloid mill 32. Thehomogenizer 34 may preferably comprise, for example, a Microfluidizer®system commercially available from Microfluidics InternationalCorporation (Newton, Mass., USA). Also suitable are homogenizers such asmodels MS18, MS45 and MC120 Series homogenizers available from the APVHomogenizer Division of APV Gaulin, Inc. (Wilmington, Mass., USA). Othersuitable homogenizers are commercially available and will be apparent tothose skilled in the art given the benefit of the present disclosure.Typically, carbon black in water prepared in accordance with the abovedescribed system will have at least about 90% agglomerates less thanabout 30 microns, more preferably at least about 90% agglomerates lessthan about 20 microns in size. Preferably, the carbon black is brokendown to an average size of 5-15 microns, e.g., about 9 microns. Exitport 38 passes the carbon black slurry from the homogenizer to themixing zone through feed line 16. The slurry may reach 10,000 to 15,000psi in the homogenizer step and exit the homogenizer at about 600 psi ormore. Preferably, a high carbon black content is used to reduce the taskof removing excess water or other carrier. Typically, about 10 to 30weight percent carbon black is preferred. Those skilled in the art willrecognize, given the benefit of this disclosure, that the carbon blackcontent (in weight percent) of the slurry and the slurry flow rate tothe mixing zone should be coordinated with the natural rubber latex flowrate to the mixing zone to achieve a desired carbon black content (inphr) in the masterbatch. The carbon black content will be selected inaccordance with known principles to achieve material characteristics andperformance properties suited to the intended application of theproduct. Typically, for example, carbon blacks of CTAB value 10 or moreare used in sufficient amount to achieve carbon black content in themasterbatch of at least about 30 phr.

[0049] The slurry preferably is used in masterbatch productionimmediately upon being prepared. Fluid conduits carrying the slurry andany optional holding tanks and the like, should establish or maintainconditions which substantially preserve the dispersion of the carbonblack in the slurry. That is, substantial reaglomeration or settling outof the particulate filler in the slurry should be prevented or reducedto the extent reasonably practical. Preferably all flow lines, forexample, are smooth, with smooth line-to-line interconnections.Optionally, an accumulator is used between the homogenizer and themixing zone to reduce fluctuations in pressure or velocity of the slurryat the slurry nozzle tip in the mixing zone.

[0050] Natural rubber latex fluid or other elastomer latex fluid passedto the mixing zone via feed line 12 and carbon black slurry fed to themixing zone via feed line 16 under proper process parameters asdiscussed above, can produce a novel elastomer composite, specifically,elastomer masterbatch crumb. Means may also be provided forincorporating various additives into the elastomer masterbatch. Anadditive fluid comprising one or more additives may be fed to the mixingzone as a separate feed stream. One or more additives also may bepre-mixed, if suitable, with the carbon black slurry or, more typically,with the elastomer latex fluid. Additives also can be mixed into themasterbatch subsequently, i.e., during the dry mixing step. Numerousadditives are well known to those skilled in the art and include, forexample, antioxidants, antiozonants, plasticizers, processing aids(e.g., liquid polymers, oils and the like), resins, flame-retardants,extender oils, lubricants, and a mixture of any of them. The general useand selection of such additives is well known to those skilled in theart. Their use in the system disclosed here will be readily understoodwith the benefit of the present disclosure. In accordance with certainalternative embodiments, curative also can be incorporated in likemanner, to produce a curable elastomer composite which may be referredto as a curable base compound.

[0051] The elastomer masterbatch crumb is passed from the discharge endof coagulum reactor 14 to suitable drying apparatus. In the preferredembodiment of FIG. 1 the masterbatch crumb undergoes multi-stage drying.It is passed first to a de-watering extruder 40 and then via conveyor orsimple gravity drop or other suitable means 41 to a drying extruder 42.In routine preferred embodiments consistent with that illustrated inFIG. 1 producing natural rubber masterbatch with carbon black filler,the de-watering/drying operation will typically reduce water content toabout 0 to 1 weight percent, more preferably 0.0 to 0.5 weight percent.Suitable dryers are well known and commercially available, including forexample, extruder dryers, fluid bed dryers, hot air or other ovendryers, and the like, such as French Mills available from the French OilMachinery Co., (Piqua, Ohio, USA).

[0052] Dried masterbatch crumb from drying extruder 42 is carried by acooling conveyor 44 to a baler 46. The baler is an optional,advantageous feature of the apparatus of FIG. 1, wherein the driedmasterbatch crumb is compressed within a chamber into form-stablecompressed blocks or the like. Typically, 25 to 75 pound quantities ofthe elastomer masterbatch are compressed into blocks or bales fortransport, further processing, etc. Alternatively, the product isprovided as pellets, for example, by chopping the crumb.

[0053] The dimensions and particular design features of the coagulumreactor 14, including the mixing zone/coagulum zone assembly, suitablefor an embodiment in accordance with FIG. 1, will depend in part on suchdesign factors as the desired throughput capacity, the selection ofmaterials to be processed, etc. One preferred embodiment is illustratedin FIG. 2 wherein a coagulum reactor 48 has a mix head 50 attached to acoagulum zone 52 with a fluid-tight seal at joint 54. FIG. 2schematically illustrates a first subsystem 56 for feeding elastomerlatex to the mixing zone, subsystem 57 for feeding carbon black slurryor other particulate filler fluid to the mixing zone, and subsystem 58for feeding an optional additive fluid, pressurized air, etc. to themixing zone. The mix head 50 is seen to have three feed channels 60, 61,62. Feed channel 60 is provided for the natural rubber latex fluid andfeed channel 62 is provided for direct feed of gas and/or additivefluid. In connection with preferred embodiments employing directinjection of additives, significant advantage is achieved in connectionwith hydrocarbon additives or, more generally, non-water miscibleadditives. While it is well known to employ emulsion intermediates tocreate additive emulsions suitable for pre-blending with an elastomerlatex, preferred embodiments in accordance with the present disclosureemploying direct injection of additives can eliminate not only the needfor emulsion intermediates, but also the equipment such as tanks,dispersing equipment, etc. previously used in forming the emulsions.Reductions in manufacturing cost and complexity can, therefore, beachieved. As discussed further below, the feed channel 61 through whichslurry is fed to the mixing zone is preferably coaxial with the mixingzone and the coagulum zone of the coagulum reactor. While only a singlefeed channel is shown to receive the elastomer latex fluid, any suitablenumber of feed channels may be arranged around the central feed channelthrough which the slurry is fed to the mixing zone. Thus, for example,in the embodiment of FIG. 2 a fourth feed channel could be providedthrough which ambient air or high pressure air or other gas is fed tothe mixing zone. Pressurized air may be injected likewise with theslurry through the central axial feed channel 61. Auxiliary feedchannels can be temporarily or permanently sealed when not in use.

[0054] The coagulum zone 52 of the coagulum reactor 48 is seen to have afirst portion 64 having an axial length which may be selected dependingupon design objectives for the particular application intended.Optionally, the coagulum zone may have a constant cross-sectional areaover all or substantially all of its axial length. Thus, for example,the coagulum reactor may define a simple, straight tubular flow channelfrom the mixing zone to the discharge end. Preferably, however, forreasons discussed above, and as seen in the preferred embodimentillustrated in the drawings, the cross-sectional area of the coagulumzone 52 increases progressively from the entry end 66 to discharge end68. More specifically, the cross-sectional area increases in thelongitudinal direction from the entry end to the discharge end. In theembodiment of FIG. 2, the coagulum zone increases in cross-sectionalarea progressively in the sense that it increases continuously followingconstant cross-sectional portion 64. References to the diameter andcross-sectional area of the coagulum reactor (or, more properly, thecoagulum zone defined within the coagulum reactor) and other components,unless stated otherwise, are intended to mean the cross-sectional areaof the open flow passageway and the inside diameter of such flowpassageway.

[0055] Elastomer composite, specifically, coagulated elastomer latex inthe form of masterbatch crumb 72, is seen being discharged from thecoagulum reactor 48 through a diverter 70. Diverter 70 is an adjustableconduit attached to the coagulum reactor at discharge end 68. It isadjustable so as to selectively pass the elastomer masterbatch crumb 72to any of various different receiving sites. This feature advantageouslyfacilitates removal of masterbatch crumb from the product stream, forexample, for testing or at the beginning of a production run wheninitial process instability may result temporarily in inferior product.In addition, the diverter provides design flexibility to direct productfrom the coagulum reactor to different post-processing paths. Inaccordance with the preferred embodiment of FIG. 1, the masterbatchcrumb 72 being discharged from coagulum reactor 48 through diverter 70is seen to be received by a drier 40.

[0056] The cross-sectional dimension of coagulum reactor 48 is seen toincrease at an overall angle α between entry end 66 and discharge end68. Angle α is greater than 0° and in preferred embodiments is less than45°, more preferably less than 15°, most preferably from 0.5° to 5°. Theangle α is seen to be a half angle, in that it is measured from thecentral longitudinal axis of the coagulum zone to a point A at the outercircumference of the coagulum zone at the end of the coagulum reactor.In this regard, it should be understood that the cross-sectional area ofthe upstream portion of the coagulum reactor, that is, the portion nearthe entry end 66, preferably increases sufficiently slowly to achievequasi-molding of the coagulum in accordance with the principlesdiscussed above. Too large an angle of expansion of the coagulum zonemay result in the elastomer masterbatch not being produced in desirablecrumb form of globules or worms and simply spraying through the coagulumreactor. Increasing the bore of the coagulum reactor too slowly canresult, in certain embodiments, in backup or clogging of the feeds andreaction product into the mix head. In a downstream portion of thecoagulum zone, wherein the latex has been substantially coagulated andflow has become essentially plug flow, the coagulum zone may extendeither with or without increase in cross-sectional area. Thus, referencehere to the coagulum zone in preferred embodiments having aprogressively increasing cross-sectional area should be understood torefer primarily to that portion of the coagulum zone wherein flow is notsubstantially plug flow.

[0057] The cross-sectional area of the coagulum zone (that is, at leastthe upstream portion thereof, as discussed immediately above) mayincrease in step-wise fashion, rather than in the continuous fashionillustrated in the embodiment of FIG. 2. In the embodiment illustratedin FIG. 3, a continuous flow system for production of elastomermasterbatch in accordance with the method and apparatus disclosed here,is seen to include a mix head/coagulum zone assembly wherein thecross-sectional area of the coagulum zone increases in step-wisefashion. Preferably, the individual sections of the coagulum zone insuch a step-wise embodiment have a faired connection to adjacentsections. That is, they combine to form a smooth and generallycontinuous coagulum zone surface, as opposed, for example, to a sharp orinstantaneous increase in diameter from one section to the next. Thecoagulum zone of FIG. 3 increases in three steps, such that there arefour different sections or sub-zones 74-77. Consistent with the designprinciples discussed immediately above, the cross-sectional area ofcoagulum zone 53 increases from the entry end 66 to point A at thedischarge end 68 at an overall angle which achieves the necessary flowcontrol in the upstream portion of the coagulum reactor. The firstsection 74 can be taken as including (a) the constant diameter portionof the mix head 50 immediately downstream of the mixing zone, and (b)the same or similar diameter portion connected thereto at joint 54 atthe entry end 66. This first section has a constant cross-sectionaldiameter D₁ and an axial dimension or length L₁. In this first section74 the length L₁ should be greater than three times the diameter D₁,more preferably greater than five times D₁, and most preferably fromabout 12 to 18 times D₁. Typically, this section will have a length ofabout fifteen times D₁. Each subsequent section preferably has aconstant cross-sectional dimension and cross-sectional areaapproximately double that of the preceding (i.e., upstream) section.Thus, for example, section 75 has a constant cross-sectional dimensionand a cross-sectional area which is twice that of section 74. Similarly,the cross-sectional area of section 76 is double that of section 75, andthe cross-sectional area of section 77 is double that of section 76. Ineach of sections 75-77, the length is preferably greater than threetimes its diameter, more preferably about three to seven times itsdiameter and generally about five times its diameter. Thus, for example,in section 76 longitudinal dimension L₃ is preferably about five timesits diameter D₃. A mix head and coagulum zone assembly corresponding tothe embodiment of FIG. 3 is shown in FIG. 4 partially in section view.Mix head 50 is integral with coagulum zone extender 53 via joint 54. Itdefines a mixing zone wherein multiple feed channels 60, 61, 62 form ajunction, with an elongate, substantially cylindrical channel 80substantially coaxial with the coagulum zone portion within extender 53.It will be recognized that it is not essential to the operability of themethod and apparatus disclosed here, to precisely define the boundariesof the mixing zone and/or coagulum zone. Numerous variations arepossible in the design of the flow channels junction area, as will beapparent to those skilled in the art given the benefit of the presentdisclosure. In that regard, as a generally preferred guideline, inembodiments of the type illustrated in FIG. 4, for example, the slurrytip 67 generally is upstream of the beginning of cylindrical portion 80,being approximately centered longitudinally in the junction of the feedchannels. In such embodiments, preferably, the minimum cross-sectionalarea defined by the imaginary cone from the slurry tip 67 to thecircumferential perimeter at the beginning of the cylindrical portion 80is advantageously greater than, or at least equal to, thecross-sectional area of the latex feed channel 60. Preferably, bothchannel 80 and at least the upstream portion of the coagulum zonewherein flow turbulence exists prior to substantially completecoagulation of the elastomer latex, have a circular cross-section.

[0058] The means for feeding carbon black slurry or other particulatefiller fluid is seen to comprise a feed tube 82 extending substantiallycoaxially with the mixing chamber to an opening or slurry nozzle tip 67which is open toward the coagulum zone. This is a highly advantageousfeature of the preferred embodiments discussed here. The carbon blackslurry, as noted above, is fed to the mixing zone at very high velocityrelative the feed velocity of the latex, and the axial arrangement ofnarrow bore feed tube 82 results in excellent development of flowturbulence. The diameter D_(m) of the channel 80 (which, as noted above,is preferably substantially equal to the diameter D₁ of immediatelyfollowing portion of section 74 of the coagulum zone) preferably is atleast twice the inside diameter of slurry feed tube 82, more preferablyabout four to eight times the diameter of feed tube 82, typically aboutseven to eight times that diameter. Feed tube 82 is seen to form afluid-tight seal with the entry port 83 at the upstream end of feedchannel 61 of mix head 50. The diameter of the axial feed tube 82 isdetermined largely by the required volumetric flow rate and axialvelocity of the slurry as it passes through the slurry nozzle tip 67into the mixing chamber. The correct or required volume and velocity canbe readily determined by those skilled in the art given the benefit ofthis disclosure, and will be a function, in part, of the concentrationand choice of materials. Embodiments such as that illustrated anddisclosed here, wherein the feed tube for the carbon black slurry isremovable, provide desirable flexibility in manufacturing differentmasterbatch compositions at different times. The feed tube used in oneproduction run can be removed and replaced by a larger or smaller boretube appropriate to a subsequent production. In view of the pressure andvelocity at which the slurry exits the feed tube, it may be referred toas a spray or jet into the mixing zone. This should be understood tomean in at least certain embodiments, high speed injection of the slurryinto an area already substantially filled with fluid. Thus, it is aspray in the sense of its immediate distribution as it passes throughthe slurry nozzle tip, and not necessarily in the sense of free-flyingmaterial droplets in a simple spreading trajectory.

[0059] The additional feed channels 60 and 62 are seen to form ajunction 84, 85, respectively, with feed channel 60 and downstreamchannel 80 at an angle β. The angle β may in many embodiments have avalue from greater than 0° to less than 180°. Typically, β may be, forexample, from 30°-90°. It is desirable to avoid a negative pressure,that is, cavitation of the latex fluid as it is entrained by the highvelocity slurry exiting at slurry nozzle tip 67, since this maydisadvantageously cause inconsistent mixing leading to inconsistentmasterbatch product. Air or other gas can be injected or otherwise fedto the mixing zone to assist in breaking any such vacuum. In addition,an expanded feed line for the natural rubber latex leading to the entryport 86 of feed channel 60 is desirable to act as a latex fluidreservoir. In the preferred embodiment of FIG. 4, latex feed channel 60intersects the mixing zone adjacent slurry nozzle tip 67. Alternatively,however, the latex feed channel can intersect the mixing channelupstream or downstream of the slurry nozzle tip 67.

[0060] The carbon black slurry or other particulate filler fluidtypically is supplied to feed tube 82 at a pressure above about 300psig, such as about 500 to 5000 psig, e.g. about 1000 psig. Preferablythe liquid slurry is fed into the mixing zone through the slurry nozzletip 67 at a velocity above 100 ft. per second, preferably about 100 toabout 800 ft. per second, more preferably about 200 to 500 ft. persecond, for example, about 350 feet per second. Arrows 51 in FIG. 4represent the general direction of flow of the elastomer latex andauxiliary feed materials through feed channels 60 and 62 into thechannel 80 below slurry nozzle tip 67. Thus, the slurry and latex fluidsare fed to the mixing zones at greatly different feed stream velocities,in accordance with the numbers set forth above. While not wishing to bebound by theory, it presently is understood that the differential feedachieves latex shear conditions in the mixing zone leading to goodmacro-dispersion and coagulation.

[0061] An alternative preferred embodiment is illustrated in FIGS. 5 and6 wherein the single axial feed tube 82 in the embodiment of FIG. 4 isreplaced by multiple axially extending feed tubes 90-92. Even greaternumbers of feed tubes may be employed, for example, up to about 6 or 8axially-extending feed tubes. Advantageously, production flexibility isachieved by using different feed tubes of different diameter forproduction of different formulations. Also, multiple feed tubes can beused simultaneously to achieve good flow turbulence within the mixingzone and coagulum zone of the coagulum reactor.

[0062] An alternative embodiment of the mix head is illustrated in FIG.7. Mix head 150 is seen to define a mixing zone 179. An axial feedchannel 161 receives a feed tube 182 adapted to feed carbon black slurryor other particulate filler fluid at high velocity into the mixingchamber 179. It can be seen that the central bore in feed tube 182terminates at slurry nozzle tip 167. A constant diameter nozzle land 168is immediately upstream of slurry nozzle tip 167, leading to a largerbore area 169. Preferably the axial dimension of land 168 is about 2 to6, e.g. about 5, times its diameter. A second feed channel 160 forms ajunction 184 with the mixing zone 179 at a 90° angle for feedingelastomer latex fluid to the mixing zone. The cross-sectional diameterof the latex fluid feed channel 160 is substantially larger than thecross-sectional diameter of the slurry nozzle tip 167 and land 168.Without wishing to be bound by theory, the axial elongation of nozzleland 168, coupled with the expanded diameter bore section upstream ofthe nozzle land, is believed to provide advantageous stability in theflow of slurry through feed tube 182 into the mixing zone 179. The boreof feed tube 182 is found to function well with a 20° chamfer, that is,conical area 169 which expands in the upstream direction at about a 20°angle. Downstream of mixing zone 179 is an elongate coagulum zone.Consistent with the principles discussed above, such coagulum zone needbe only marginally elongate. That is, its axial dimension need be onlymarginally longer than its diameter. Preferably, however, aprogressively enlarged coagulum zone is used.

[0063] As discussed above, coagulation of the elastomer masterbatch issubstantially complete at or before the end of the coagulum reactor.That is, coagulation occurs without the necessity of adding a stream ofcoagulant solution or the like. Coagulation may occur in the mixingzone. The mixing zone may be considered all or portion of the coagulumzone for this purpose. Also, reference to substantially completecoagulation prior to the elastomer masterbatch exiting the coagulumreactor is not meant to exclude the possibility of subsequent processingand follow-on treatment steps, for any of various purposes appropriateto the intended use of the final product. In that regard, substantiallycomplete coagulation in preferred embodiments of the novel methoddisclosed here employing natural rubber latex means that at least about95 weight percent of the rubber hydrocarbon of the latex is coagulated,more preferably at least about 97 weight percent, and most preferably atleast about 99 weight percent is coagulated.

[0064] The masterbatch (or other elastomer composite) produced by thewet mixing step optionally undergoes any suitable further processingprior to addition of additional elastomer in the dry mixing step of thewet/dry method disclosed here. Suitable apparatus for the dry mixingstep is commercially available and will be apparent to those skilled inthe art given the benefit of this disclosure. Suitable dry mixingapparatus include, for example, Banbury mixers, mills, roller mixers,etc. The coagulum from the wet mixing step, with or without any furtherintermediate processing, is introduced into the Banbury mixer or othermixing device along with the additional elastomer in any suitable orderand relative proportion suitable to the intended use or application. Itwill be within the ability of those skilled in the art, given thebenefit of this disclosure to determine suitable order of addition andrelative proportion for the wet mixing product and the additionalelastomer. Likewise, it will be within the ability of those skilled inthe art given the benefit of this disclosure to select suitableadditional ingredients for addition during the dry mixing step suitableto the intended use or application, for example, extender oil,curatives, and other additives known for use in elastomer composites andelastomer composite blends of the general type disclosed here.

[0065] The method and apparatus disclosed and described here produceelastomer composite blends having excellent physical properties andperformance characteristics. Novel elastomer composite blends of thepresent invention include masterbatch compositions produced by theabove-disclosed method and apparatus, as well as intermediate compoundsand finished products made from such masterbatch compositions. Notably,elastomer masterbatch can be produced using natural rubber latex (latexconcentrate or field latex), along with various grades of carbon blackfiller, having excellent physical properties and performancecharacteristics. Carbon blacks presently in broad commercial use forsuch application as tire tread have been used successfully, as well ascarbon blacks heretofore considered unsuitable for commercial use inknown production apparatus and methods. Those unsuitable because theirhigh surface area and low structure rendered them impractical to achieveacceptable levels of macro-dispersion at routine commercial loadinglevels for the carbon black and/or to preserve the molecular weight ofthe elastomer are highly preferred for certain applications of the novelelastomer composite blends disclosed here. Such elastomer compositeblend are found to have excellent dispersion of the carbon black in theelastomer. Moreover, these advantageous results were achieved withoutthe need for a coagulation step involving a treatment tank or stream ofacid solution or other coagulant. Thus, not only can the cost andcomplexity of such coagulant treatments be avoided, so too the need tohandle effluent streams from such operations also is avoidable also isavoided.

[0066] Prior known dry mastication techniques could not achieve equaldispersion of fillers in elastomer composite blends without significantmolecular weight degradation and, therefore, could not produce the novelnatural rubber compositions made in accordance with certain preferredembodiments of the present invention. In that regard, novel elastomercomposite blends are disclosed here having excellent macro-dispersion ofcarbon black in natural rubber, even of carbon blacks having a structureto surface area ratio DBPA:CTAB less than 1.2 and even less than 1.0,with high molecular weight of the natural rubber. Known mixingtechniques in the past did not achieve such excellent macro-dispersionof carbon black without significant molecular weight degradation of thenatural rubber and, therefore, did not produce the novel masterbatchcompositions and other elastomer composites of the present invention.Preferred novel elastomer composite blends in accordance with thisdisclosure, having carbon black macro-distribution levels not heretoforeachieved, can be used in place of prior known elastomer materials havingpoorer macro-dispersion. Thus, elastomer composite blends disclosed herecan be used as cured compounds in accordance with known techniques. Suchnovel cured compounds are found in preferred embodiments to havephysical characteristics and performance properties generally comparableto, and in some instances significantly better than, those of otherwisecomparable cured compounds comprising masterbatch of poorermacro-dispersion. Elastomer composite blends can be produced inaccordance with the present invention, with reduced mixing time, reducedenergy input, and/or other cost savings.

[0067] As used here, the carbon black structure can be measured as thedibutyl phthalate adsorption (DBPA) value, expressed as cubiccentimeters of DBPA per 100 grams carbon black, according to theprocedure set forth in ASTM D2414. The carbon black surface area can bemeasured as CTAB expressed as square meters per gram of carbon black,according to the procedure set forth in ASTM D3765-85. It will berecognized that other factors affecting the level of dispersionachievable using the method and apparatus disclosed here, include theconcentration of the carbon black in the slurry, total energy input intothe slurry and energy input during mixing of the fluid streams, etc.

[0068] The macro-dispersion quality of carbon black in natural rubbermasterbatch disclosed here is significantly better than that inpreviously known masterbatch of approximately equal MW_(sol) (weightaverage). In some preferred embodiments excellent carbon blackdistribution is achieved with MW_(sol) approximately equal to that ofnatural rubber in the field latex state, (e.g., approximately 1,000,000)a condition not previously achieved. The dispersion quality advantage isespecially significant in the above mentioned preferred embodimentsusing carbon black with low structure and high surface area, e.g., DBPAless than 110 cc/10 g, CTAB greater than 45 to 65 m²/g, and DBPA:CTABless than 1.2 and preferably less than 1.0.

EXAMPLES

[0069] Test Procedures

[0070] The following test procedures were used in the examples andcomparisons presented below.

[0071] 1. Bound Rubber: A sample weighing 0.5 g.±0.025 g. is weighed andplaced in 100 ml. toluene in a sealed flask and stored at ambienttemperature for approximately 24 hours. The toluene is then replacedwith 100 ml. fresh toluene and the flask is stored for 4 days. Thesample is then removed from the solvent and air-dried under a hood atambient temperature for 24 hours. The sample is then further dried in avacuum oven at ambient temperature for 24 hours. The sample is thenweighed and the bound rubber is calculated from the weight loss data.

[0072] 2. MW_(sol): As used in this disclosure and in the claims,MW_(sol) refer to weight average molecular weight of the sol portion ofthe natural rubber. Standard GPC techniques for molecular weightmeasurement were followed in accordance with the following: 2.1 Two 10μm10⁶ Å columns, a 10μm 500Å column and a 10μm mixed bed column fromPolymer Laboratories, UK. 2.2 UV detection at 215 nm. 2.3 Solvent: Tetrahydro furan (THF) 2.4 Concentration, nominally 2 mg/ml in THF. 2.5Samples are left to dissolve in THF for 3 days, stabilized with BHT. 2.6Solutions are centrifuged to separate any gel and the supernatant isinjected onto the column. 2.7 Sample Preparations Sample preparation isdesigned to prepare sol concentrations in the range of 0.5 to 0.05percent by weight to provide a good detector response for accuratemeasurement of the molecular

[0073] weight distribution. Depending on the filler loading, sampleweight is adjusted according to the following formula:

sample wt.=(100+filler loading (phr))*20/100 mg+/−2 mg

[0074] Samples are placed in UV protected vials and dissolved in 4 mL ofstabilized tetrahydrofuran (THF) containing 0.02%butylated-hydroxyltoluene (BHT) for three days. The supernatant from thedissolution step, containing mostly the sol portion, is transferred toTeflon centrifuge tubes and centrifuged in an Avanti 30 (Beckman)centrifuge for 60 minutes at 26,000 revolutions per minute(corresponding to a maximum field strength of 57,500 g). At this fieldstrength, a majority of the gel phase sediments allowing a gel-freesupernatant. This gel-free solution is diluted at 1:5, again usingstabilized THF. At this point, the samples are transferred to GPC vialsand placed inside a Waters 717 Auto-Sampler (Water Corporation, Milford,Mass., USA) in preparation for the GPC testing.

[0075] Molecular Weight Determination The weight average molecularweight of the sol portion MW_(sol) is then determined. Using Milleniumsoftware (available from Waters Corporation, Milford, Mass., USA) abaseline is defined using a valley-to-valley mode within the timeincrements of 15 and 35 minutes. This time increment is appropriate forthe column set described above in paragraph 2.1 with the mobile phaseflow rate set at 0.75 mL/min. Once a reasonable baseline is establishedthe distribution can be determined. The elution time is converted tomolecular weight. Polystyrene solutions made from commercially availablestandards (EasiCal: Polymer Laboratories, U.K.) are prepared containinga series of molecular weights with very narrow distributions. Theconversion of polystyrene molecular weight to polyisoprene molecularweight equivalents is based on the universal calibration method ofBenoit and coworkers. The hydrodynamic radius is proportional to theproduct of the molecular weight times the intrinsic viscosity. Afterconverting the polystyrene molecular weights to polyisopreneequivalents, the calibration curve relates absolute molecular weight toelution time. The standards are run under conditions identical to thesamples, and the standards are integrated to assign the appropriatemolecular weight for a given elution time, based on a best fit to thestandards data. Once the time based distribution is properly convertedto molecular weight, the appropriate molecular weight averages arecalculated by the Waters' Millenium software.

[0076] 3. Mooney Viscosity: Standard procedures were followed for ML(1+4)@100° C. 4. Test Sample Cure Conditions: Test pieces were cured to150° C. for the time periods indicated below: 4.1 Tensile Sheet: 20 min.4.2 Resilience: 23 min. 4.3 Hardness: 23 min. 4.4 Heat Build-Up: 25 min.

[0077] 5. Dispersion: The Cabot Dispersion Chart method is used withsubjective evaluation of 50×optical micrographs. (ASTM D2663 Method).

[0078] 6. Stress-Strain: Tested to BS903:A2 and ISO 37.

[0079] 7. Hardness: Tested to ISO 48 (1994), temperature 23° C.

[0080] 8. Resilience: Tested to BS903:A8 (1990), Method A, temperature23° C. (8 mm molded disc test piece).

[0081] 9. Heat Buildup: Tested to ASTM D623, Method A. 9.1 Starttemperature: 23° C. 9.2 Static load: 24 lbs. 9.3 Stroke: 0.225 inches.9.4 Frequency: 30 Hz. 9.5 Run for 30 minutes.

[0082] 10. Tan δ: Measured on Rheometrics® model RDS II. Reported valuesare maximums from strain sweeps. Strain sweeps at 0°, 30°, and 60° C., 1Hz, and 0.1% to 60% strain.

[0083] 11. Crack Growth Resistance: Measured in accordance with ASTMD3629-94

Example A

[0084] Elastomer masterbatch was produced in accordance with the presentinvention. Specifically, an elastomer masterbatch was producedcomprising standard natural rubber field latex from Malaysia with 52.5phr filler consisting of carbon black of commercial grade N234 availablefrom Cabot Corporation. The properties of the natural rubber field latexare provided in Table 1 below. TABLE 1 Natural Rubber Latex Properties %Dry % Total Nitrogen Volatile ML(1 + 4) Additives Rubber Solids % Ashppm Fatty Acid @100 C 0.15% HNS^(a) 28.4 34.2 0.38 0.366 0.052 68 0.3%NH3, ZnO, TMTD^(b)

[0085] The full compound formulation is set forth in Table 2 below, andis representative of a commercial truck tire tread known to haveexcellent resistance to reversion during cure. TABLE 2 MasterbatchFormulation Ingredient Parts by Wt. Rubber 100 Carbon Black 52.5 ZnO 4.0Stearic acid 2.0 6PPD (antioxidant) 2.0 Sunproof Improved (wax) 2.0Ennerflex 74 (aromatic oil) 3.0 Total 165.5

[0086] The elastomer masterbatch production apparatus was substantiallyidentical to the apparatus described above with reference to FIGS. 1 and7 of the drawings. The slurry nozzle tip (see reference No. 167 in FIG.7) was 0.039 inch diameter with a land (see reference No. 168 in FIG. 7)having an axial length of 0.2 inch. The coagulum zone was 0.188 inchdiameter and had 0.985 inch axial length of constant diameter betweenthe mixing zone and its discharge end. Preparation of the masterbatch isdescribed in further detail immediately below.

[0087] 1. Carbon Black Slurry Preparation. Bags of carbon black weremixed with deionized water in a carbon black slurry tank equipped withan agitator. The agitator broke the pellets into fragments and a crudeslurry was formed with 12.5 wt. % carbon black. During operation, thisslurry was continually pumped by an air diaphragm pump to a colloid millfor initial dispersion. The slurry was then fed by a progressing cavitypump to a homogenizer, specifically, a model M3 homogenizer from APVGaulin, Inc. The homogenizer produced a finely ground slurry. The slurryflow rate from the homogenizer to the mixing zone was set by thehomogenizer speed, the homogenizer acting as a high-pressure positivedisplacement pump. Slurry flow rate was monitored with a Micromotion®mass flow meter. The carbon black slurry was fed to the homogenizer at apressure ranging from 50 to 100 psig and the homogenization pressure wasset at 4000 psig, such that the slurry was introduced as a jet into themixing zone at a flow rate of 4.1 to 4.4 lb/min and at a velocity ofabout 130 ft/sec.

[0088] 2. Latex Delivery. The latex was charged to a 100 gallonpressurized feed tank.

[0089] Antioxidant emulsion was added to the latex prior to charging.Antioxidants were added consisting of 0.3 phr tris nonyl phenylphosphite (TNPP) and 0.4 phr Santoflex® 134 (alkyl-aryl p-phenylenediamine mixture). Each of the antioxidants was prepared as a 15 wt. %emulsion using 3 parts potassium oleate per 100 parts antioxidant alongwith potassium hydroxide to adjust the emulsion to a pH of approximately10. Also, 3 phr extender oil was added. Air pressure (51 psig) was usedto move the latex from the feed tank to the mixing zone of the coagulumreactor. The latex flow rate was 3.2 to 3.4 lbs/min and about 3.8 feetper second, and was automatically metered and controlled with aMicromotion® mass flow meter and a rubber tube pinch valve. The desiredcarbon black loading of a 52.5 phr was obtained by maintaining properratio of the latex feed rate to the carbon black slurry feed rate.

[0090] 3. Carbon Black and Latex Mixing. The carbon black slurry andlatex were mixed by entraining the latex into the carbon black slurry.During entrainment, the carbon black was intimately mixed into the latexand the mixture coagulated. Soft, wet spongy “worms” of coagulum exitedthe coagulum reactor.

[0091] 4. Dewatering. The wet crumb discharged from the coagulum reactorwas about 79% water. The wet crumb was dewatered to about 5 to 10%moisture with a dewatering extruder (The French Oil Mill MachineryCompany; 3½ in. diameter). In the extruder, the wet crumb was compressedand water squeezed from the crumb and through a slotted barrel of theextruder.

[0092] 5. Drying & Cooling. The dewatered crumb dropped into a secondextruder where it was again compressed and heated. Water was flashed offupon expulsion of the crumb through the dieplate of the extruder.Product exit temperature was approximately 300° F. and moisture contentwas about 0.5 to 1 wt. %. The hot, dry crumb was rapidly cooled(approximately 20 seconds) to about 100° F. by a forced air vibratingconveyor. The resulting dry crumb had about 66. wt. % rubber solids andabout 33. wt. % carbon black.

Example B

[0093] A control masterbatch was prepared by dry mastication. Thecontrol employed the same formulation as Example A (see Table 2 above),except that the natural rubber was SMR 10 rather than latex. It wasprepared by premastication of the rubber in a OOC Banbury mixer(approximately 3 kg) at 50 rpm using 10 phr carbon black. Thepremastication was performed for approximately 3 min. to a total of 800MJ/m³.

Comparisons of Example A and Example B

[0094] The masterbatch of Example A and the control masterbatch ofExample B were compounded in a two-stage mixing operation in a OOCBanbury mixer (approximately 3 kg). Table 3 below sets forth the mixingschedule for the first stage. It can be seen that the Example Amasterbatch followed a modified mixing schedule. TABLE 3 Stage 1 MixingSchedules Time Example B (min) Example A Dry Mix Control 0.0 Allingredients Pre-Masticated Rubber 0.5 Carbon Black and Oil 1.0 Sweep 1.5Remaining Ingredients 2.0 2.5 Sweep 3.0 X dump at approx. 700 MJ/m³ dumpat approx. 1,000 MJ/m³

[0095] In the second stage, curatives listed in Table 4 below were addedwith a further mixing cycle of 500 MJ/m³. TABLE 4 Final Stage CurativeAddition Ingredient Parts by Wt. Stage 1 compound 165.5 Goodyear Winstay100 (antioxidant) 1.0 TBBS (sulfur accelerator) 1.8 Sulfur 1.0 Total169.3

[0096] Thus, Banbury mixing energy for the compounding of Example Amasterbatch was about 53% of the Banbury mixing energy required for thepremastication and compounding of the control material of Example B.Despite the reduced energy input, the Example A material was found tohave very good macro-dispersion, and the molecular weight (weightaverage) of its sol portion MW_(sol) was substantially higher than thatof the control. These data are summarized in Table 5 below. TABLE 5Compounding and Curing Data ML (1 + 4, Mix Energy (MJ/m³) 100C) Pre-Stage MW Sample Masticate Stage 1 Final Total 1 Final wt. av. Example A0 694 500 1,194 102 72 444,900 Example B 800 965 500 2,265  92 67327,000

[0097] Additional testing results for the cured (unaged) Example A andcontrol material are set forth in Table 6 below. TABLE 6 Additional TestData 100% Modulus 300% Modulus Elongation at Heat Build-Up Max Tan DeltaSample Hardness (MPa) (MPa) Tensile (MPa) Break (%) Resiliance (%) (°C.) 60° C. 30° C. 0° C. Example A 71 2.82 16.1 28.7 526 56.5 70.5 0.2030.240 0.290 Example B 72 3.12 16.2 28.5 511 57.6 76.5 0.206 0.236 0.286

Example C

[0098] Elastomer masterbatch was produced in accordance with the presentinvention. Specifically, an elastomer masterbatch was producedcomprising standard natural rubber field latex from Malaysia with 55 phrfiller consisting of carbon black of commercial grade Regal® 660available from Cabot Corporation. The compound formulation (excludingminor ordinary latex additives) is set forth in Table 7 below. TABLE 7Masterbatch Formulation Ingredient Parts by Wt. Rubber 100 Carbon Black55. Santoflex 134 (antioxidant) 0.4 TNPP (antioxidant) 0.3 Total 155.7

[0099] The elastomer masterbatch production apparatus was substantiallyidentical to the apparatus described above with reference to FIGS. 1, 3and 7 of the drawings. The slurry nozzle tip (see reference No. 167 inFIG. 7) was 0.025 inch diameter with a land (see reference No. 168 inFIG. 7) having an axial length of 0.2 inch. The coagulum zone (see No.53 in FIG. 3) included a first portion of 0.188 inch diameter andapproximately 0.985 inch axial length (being partly within the mix-headand party within the extender sealed thereto); a second portion of 0.266inch diameter and 1.6 inch axial length; a third portion of 0.376 inchdiameter and 2.256 axial length; and a fourth portion of 0.532 inchdiameter and 3.190 inch axial length. In addition, there are axiallyshort, faired interconnections between the aforesaid portions.Preparation of the masterbatch is described in further detailimmediately below.

[0100] 1. Carbon Black Slurry Preparation. Bags of carbon black weremixed with deionized water in a carbon black slurry tank equipped withan agitator. The agitator broke the pellets into fragments and a crudeslurry was formed with 14.9 wt. % carbon black. The crude slurry wasrecirculated using a pipeline grinder. During operation, this slurry wascontinually pumped by an air diaphragm pump to a colloid mill forinitial dispersion. The slurry was then fed by a progressing cavity pumpto a homogenizer, specifically, Microfluidizer Model M210 fromMicrofluidics International Corporation for pressurizing and shear, toproduce a finely ground slurry. The slurry flow rate from themicrofluidizer to the mixing zone was set by the microfluidizer speed,the microfluidizer acting as a high-pressure positive displacement pump.Slurry flow rate was monitored with a Micromotion® mass flow meter. Thecarbon black slurry was fed to the microfluidizer at a pressure of about130 psig and the output pressure was set at 3000 psig to an accumulatorset at 450 psig output pressure, such that the slurry was introduced asa jet into the mixing zone at a flow rate of about 3.9 lb/min and at avelocity of about 300 ft/sec.

[0101] 2. Latex Delivery. The latex was charged to a tank, specifically,a 55 gallon feed drum. Antioxidant emulsion was added to the latex priorto charging. Antioxidants were added consisting of 0.3 phr tris nonylphenyl phosphite (TNPP) and 0.4 phr Santoplex® 134 (alkyl-arylp-phenylene diamine mixture). Each of the antioxidants was prepared as a40 wt. % emulsion using 4 parts potassium oleate per 100 partsantioxidant along with potassium hydroxide to adjust the emulsion to apH of approximately 10. A peristaltic pump was used to move the latexfrom the feed tank to the mixing zone of the coagulum reactor. The latexflow rate was 3.2 to 3.3 lbs/min and about 3.9 feet per second, and wasmetered with a Endress+Hauser (Greenwood, Ind., USA) mass flow meter.The desired carbon black loading of a 55 phr was obtained by maintainingproper ratio of the latex feed rate to the carbon black slurry feedrate.

[0102] 3. Carbon Black and Latex Mixing. The carbon black slurry andlatex were mixed by entraining the latex into the carbon black slurry.During entrainment, the carbon black was intimately mixed into the latexand the mixture coagulated. Soft, wet spongy “worms” of coagulum exitedthe coagulum reactor.

[0103] 4. Dewatering. The wet crumb discharged from the coagulum reactorwas about 78% water. The wet crumb was dewatered to about 12 to 13%moisture with a dewatering extruder (The French Oil Mill MachineryCompany; 3½ in. diameter). In the extruder, the wet crumb was compressedand water squeezed from the crumb and through a slotted barrel of theextruder.

[0104] 5. Drying & Cooling. The dewatered crumb dropped into a secondextruder where it was again compressed and heated. Water was flashed offupon expulsion of the crumb through the dieplate of the extruder.Product exit temperature was approximately 280° F. to 370° F. andmoisture content was about 0.3 to 0.4 wt. %. The hot, dry crumb wasrapidly cooled (approximately 20 seconds) to about 100° F. by a forcedair vibrating conveyor.

Examples D and E

[0105] Two dry mix control masterbatches were prepared by drymastication. The controls employed the same formulation as Example C(see Table 7 above), except that in Example D the rubber was RSS1 NRrather than latex. In Example E the rubber was SMR 10 NR. Each wasprepared by premastication of the rubber in a BR Banbury mixer. Therubber of Example D was masticated at 118 rpm for 10 minutes. The rubberof Example E was masticated at 77 rpm for 4 minutes.

Comparison of Examples C, D and E

[0106] The masterbatch of Example C and the two control masterbatches ofExample D and E were compounded in a BR Banbury mixer. Table 8 belowsets forth the compounding schedules. TABLE 8 Compounding SchedulesStage II (Final) Masterbatch Pre-Mastication Stage I Mixing MixingExample C No No BR Banbury 77 rpm, 4.5 min. Example D BR Banbury BRBanbury BR Banbury 77 mixer 118 rpm, mixer 77 rpm, 3 rpm, 4.5 min. 10min min. Example E BR Banbury BR Banbury BR Banbury 77 mixer 77 rpm, 4mixer 77 rpm, 8 rpm, 4.5 min. min. min.

[0107] The compounding formulation is given in Table 9 below. TABLE 9Stage II Curative Addition Ingredient Parts by Wt. Example 4 Masterbatchor 155 Example 5 or 6 Stage 1 Dry Mix Azo 66 (zinc oxide) 4.0 Hystrene5016 (stearic acid) 2.0 Santoflex 13 (antioxidant) 2.0 Sunproof Improved(wax) 2.0 Wingstay 100 (antioxidant) 1.0 Santocure NS (sulfuraccelerator) 1.8 Sulfur 1.0 Total: 168.8

[0108] All three compounds exhibited well-behaved cure with minimalreversion. Despite the reduced energy input, the Example C material wasfound to have significantly better macro-dispersion than the dry mixcontrols, and the molecular weight (weight average) of its sol portionMW_(sol) was substantially higher than that of the controls. These dataare summarized in Table 10 below. TABLE 10 Masterbatch and CompoundProperties Example C Example D Example E Masterbatch Properties MooneyViscosity 125 124 126 ML(1 + 4)@100C Bound Rubber 50 32 44 (%) MW sol(x10⁻⁶) 0.678 .466 .463 Percent .12 1.48 2.82 Undispersed Area (D %)Compound Properties Hardness 62 65 62 100% Modulus 239 315 270 (psi)300% Modulus 1087 1262 1216 (psi) Tensile strength 4462 4099 4344 (psi)Elongation, % 675 591 600 Max. Tan Delta 0.189 .237 .184 @ 60 C (StrainSweep) Crack Growth 0.8 5.0 5.8 Rate (cm/per million cycles)

Additional Examples and Comparisons

[0109] Highly preferred elastomer composites in accordance with thepresent invention were produced in accordance with the method andapparatus disclosed above. In particular, novel masterbatch compositionswere formed of natural rubber latex and carbon black filler, havingsignificantly better macro-dispersion levels and/or natural rubbermolecular weight than heretofore found in known compositions formed ofthe same or similar starting materials. FIG. 8 shows the surface areaand structure of various carbon black fillers used in these preferredmasterbatch compositions, specifically, the CTAB surface area expressedas square meters per gram of carbon black per ASTM D3765-85 and dibutylphthalate absorption (DBPA) value expressed as cubic centimeters of DBPper hundred grams carbon black per ASTM D2414 are shown. FIG. 8 is seento be divided into three different regions of carbon blacks. Region Icontains carbon blacks having lower structure and higher surface area,being those most difficult to disperse in natural rubber and otherelastomers using traditional dry mixing techniques. Hence, carbon blacksof Region I are not used commercially as widely as other carbon blacks.Masterbatch and cured elastomeric compositions made with Region I carbonblacks using traditional dry mixing techniques have poorermacro-dispersion and typically lower MW_(sol). The carbon blacks ofRegion II have higher structure than those of Region I. Typically, theyachieve reasonably good dispersion in natural rubber for vehicle tireproducts and the like if subjected to such extended dry mixing that theMW_(sol) of the natural rubber is significantly degraded. The carbonblacks of Region III of FIG. 8 have lower surface area relative theirstructure. Accordingly they have been used with acceptable dispersion innatural rubber via dry mixing, but again, with undesirable degradationof MW_(sol). The dispersion of carbon blacks of all three regions ofFIG. 8, specifically, macro-dispersion, is significantly improved in theelastomer composites disclosed here, and can be achieved withsignificantly higher MW_(sol) of the natural rubber in accordance withpreferred embodiments.

Control Samples 1-443

[0110] Control samples of masterbatch were prepared by dry mixing inaccordance with the following procedures, for purposes of comparison toelastomer composites of the present invention.

[0111] 1. Mastication of Natural Rubber

[0112] In order to produce dry masterbatches with a wide range ofmolecular weight, commercial natural rubber (RSS1, SMR CV, and SMR 10)bales were pre-masticated in a BR banbury mixer using the followingconditions (fill factor: 0.75): TABLE 11 Natural Rubber MasticationConditions Sample Rotor Speed Cooling Mastication Code Mastication (rpm)Water time (min.) M1 No M2 Yes  77 On 4 M3 Yes 118 On 6 M4 Yes 118 On10 

[0113] 2. Mixing Carbon Black with Pre-Masticated Natural Rubber

[0114] In order to prepare natural rubber dry masterbatches withdifferent levels of macro-dispersion quality, the following mixingprocedures were used in a BR Banbury mixer. The fill factor was 0.70.The masterbatch ingredients and mixing procedures are described asfollows in Table 12. TABLE 12 Natural Rubber Dry Masterbatch Formulationphr (Parts per hundred parts of rubber Ingredient by weight) NaturalRubber 100 Carbon Black See Tables Below Oil See Tables Below Santofex(antioxidant) 0.4 TNPP (antioxidant) 0.3

[0115] TABLE 13 Mixing Times Dry NR Masterbatch Sample CodePre-Masticated NR Mixing Time M1D4 M1 4 M1D3 M1 6 M1D2 M1 8 M1D1 M1 10 M2D4 M2 4 M2D3 M2 6 M2D2 M2 8 M2D1 M2 10  M3D4 M3 4 M3D3 M3 6 M3D2 M3 8M3D1 M3 10  M4D4 M4 4 M4D3 M4 6 M4D2 M4 8 M4D1 M4 10 

[0116] 3. Final Mixing of Natural Rubber Masterbatch Control Samples

[0117] To evaluate compound performance, additional ingredients wereadded to the dry masticated natural rubber masterbatch control samplesof Table 13 in accordance with the formulation shown in Table 14. TABLE14 Additional Ingredients for Final Mixing Ingredient Amount (phr) Azo66 (zinc oxide) 4.0 Hystere 5016 (stearic acid) 2.0 Santoflex 13(antioxidant) 2.0 Sunproof Improved (wax) 2.0 Wingstay 100 (antioxidant)1.0 Santocure NS (sulfur accelerator) 1.8 Sulfur 1.0

[0118] The compounds were cured in accordance with standard curetechniques at 150° C. until at least substantially completely cured,typically between 10 and 30 minutes. In that regard, the same orsubstantially the same final mixing procedures, including theformulation given above in Table 14, were used for all control samples,as well as all samples of elastomer composites of the invention preparedin the manner described below (see “Preferred Embodiments Examples)which were cured and tested for compound properties and performancecharacteristics.

[0119] The following tables 15-23 set forth the sol molecular weightMW_(sol) and macro-dispersion D(%) of control samples 1 through 443. Thesamples are grouped in the tables according to choice of carbon black.Within a given table, the samples are grouped by choice of naturalrubber and by carbon black loading and oil loading. The table headingsshow this information in accordance with standard nomenclature. Thus,for example, the heading for Table 15 “N330/55phr/0” indicates 55 phrN330 carbon black with no oil. The table sub-headings show the choice ofnatural rubber. Specifically, control samples 1 through 450 are seen tobe made from standard grade natural rubber RSS1, SMRCV and SMR10.Technical description of these natural rubbers is widely available, suchas in Rubber World Magazine's Blue Book published by Lippincott andPeto, Inc. (Akron, Ohio, USA). The molecular weight MW_(sol) of thenatural rubber prior to any premastication (M1) and after the variousamounts of premastication (M2-M4) also are shown below in Tables 15-23.TABLE 15 N330/55phr/0 RSS1 SMRCV Sample Mw_(sol) Sample Mw_(sol) CodeNo. (K) D (%) No. (K) D (%) M1 1300  971 M2 932 725 M3 664 596 M4 485482 M1D1 1 465 4.24 17 426 4.35 M1D2 2 571 3.70 18 467 3.89 M1D3 3 7064.79 19 486 4.86 M1D4 4 770 4.52 20 535 4.78 M2D1 5 445 3.66 21 380 2.44M2D2 6 490 2.68 22 398 3.71 M2D3 7 512 3.68 23 433 4.30 M2D4 8 581 3.9324 498 5.81 M3D1 9 373 1.33 25 342 3.79 M3D2 10  402 2.50 26 358 4.35M3D3 11  407 2.98 27 371 5.55 M3D4 12  452 3.35 28 408 5.01 M4D1 13  3113.63 29 311 3.66 M4D2 14  337 3.40 30 325 5.31 M4D3 15  362 5.03 31 3445.91 M4D4 16  382 5.23 32 369 5.67

[0120] TABLE 16 Black Pearl 800/55phr/0 RSS1 SMRCV Sample Mw_(sol)Sample Mw_(sol) Code No. (K) D (%) No. (K) D (%) M1 1041  869 M2 786 662M3 663 491 M4 527 420 M1D1 113 507 12.20  129 418 5.15 M1D2 114 55115.10  130 482 4.94 M1D3 115 700 10.20  131 515 6.93 M1D4 116 786 5.72132 583 8.74 M2D1 117 420 5.65 133 403 2.60 M2D2 118 441 6.50 134 4382.74 M2D3 119 549 7.70 135 434 2.83 M2D4 120 606 5.88 136 530 3.88 M3D1121 387 3.26 137 366 2.38 M3D2 122 409 2.98 138 378 2.83 M3D3 123 4563.61 139 399 3.04 M3D4 124 483 4.61 140 431 2.39 M4D1 125 339 2.13 141311 2.22 M4D2 126 367 2.23 142 332 2.27 M4D3 127 360 2.60 143 344 2.27M4D4 128 403 1.96 144 390 2.73

[0121] TABLE 17 N351/33phr/20phr RSS1 Sample Mw_(sol) Code No. (K) D (%)M1 1300  M2 803 M3 601 M1D1 401 854 2.08 M1D2 402 969 3.41 M1D3 4031040  3.68 M1D4 404 1130  4.91 M2D1 405 648 1.15 M2D2 406 668 2.16 M2D3407 675 2.98 M2D4 408 721 4.70 M3D1 409 532 1.10 M3D2 410 537 2.17 M3D3411 535 2.45 M3D4 412 558 4.06

[0122] TABLE 18A Regal 250/55phr/0 RSS1 SMRCV Sample Mw_(sol) SampleMw_(sol) Code No. (K) D (%) No. (K) D (%) M1 1332 1023 M2 896 748 M3 603581 M4 408 504 M1D1 33 585 6.95 49 609 1.93 M1D2 34 669 8.03 50 634 3.29M1D3 35 759 10.5 51 681 2.21 M1D4 36 896 14.1 52 702 4.09 M2D1 37 5802.71 53 539 2.14 M2D2 38 602 2.61 54 569 2.72 M2D3 39 631 3.61 55 5874.75 M2D4 40 667 5.43 56 595 6.25 M3D1 41 457 1.53 57 466 2.88 M3D2 42476 2.09 58 449 3.19 M3D3 43 493 2.32 59 464 4.53 M3D4 44 495 3.54 60500 5.89 M4D1 45 372 1.53 61 423 2.89 M4D2 46 382 2.09 62 433 3.42 M4D347 381 2.32 63 437 4.39 M4D4 48 403 3.54 64 447 4.73

[0123] TABLE 18B Regal 250/65/0 Regal 250/75/0 Regal 250/65/10 RSS1 RSS1RSS1 Sample Mw_(sol) Sample Mw_(sol) Sample Mw_(sol) Code No. (K) D (%)No. (K) D (%) No. (K) D (%) M1 1138 1138 1138 M2 901 901 901 M3 660 660660 M4 483 483 483 M1D1 65 570 1.50 81 539 2.87 97 661 1.89 M1D2 66 6223.25 82 624 4.50 98 702 2.69 M1D3 67 707 7.50 83 685 4.17 99 741 3.14M1D4 68 788 4.77 84 763 14.35 100 822 5.24 M2D1 69 534 1.62 85 484 4.32101 593 0.91 M2D2 70 548 4.19 86 512 2.96 102 572 3.48 M2D3 71 585 4.3187 557 4.71 103 642 4.23 M2D4 72 621 6.21 88 605 4.85 104 664 5.35 M3D173 459 3.64 89 429 2.27 105 507 2.65 M3D2 74 469 5.79 90 446 2.68 106544 2.96 M3D3 75 511 5.30 91 466 3.46 107 535 3.69 M3D4 76 541 9.13 92491 6.22 108 524 3.27 M4D1 77 380 2.34 93 368 2.11 109 416 1.85 M4D2 78392 2.86 94 372 3.13 110 413 3.18 M4D3 79 399 4.59 95 375 2.92 111 4186.96 M4D4 80 395 4.57 96 388 2.92 112 441 6.46

[0124] TABLE 19 N326/55phr/0 RSS1 SMRCV Sample Mw_(sol) Sample Mw_(sol)Code No. (K) D (%) No. (K) D (%) M1 1200 1060 M2 1030 934 M3 724 777 M4635 644 M1D1 145 550 3.49 161 644 1.15 M1D2 146 636 3.54 162 661 1.32M1D3 147 650 5.89 163 697 1.35 M1D4 148 724 4.79 164 732 2.01 M2D1 149517 3.16 165 590 1.50 M2D2 150 572 2.41 166 621 1.56 M2D3 151 613 3.11167 641 2.22 M2D4 152 696 4.37 168 676 2.31 M3D1 153 489 2.78 169 5511.22 M3D2 154 521 1.93 170 550 1.62 M3D3 155 504 3.14 171 563 2.06 M3D4156 538 2.81 172 578 2.68 M4D1 157 415 1.74 173 487 1.96 M4D2 158 4472.17 174 495 2.22 M4D3 159 466 3.13 175 505 2.99 M4D4 160 469 2.93 176526 3.37

[0125] TABLE 20 N110/55phr/0 RSS1 SMRCV Sample Mw_(sol) Sample Mw_(sol)Code No. (K) D (%) No. (K) D (%) M1 937 730 M2 764 653 M3 569 541 M4 449463 M1D1 369 360 1.24 385 334 1.28 M1D2 370 426 2.50 386 339 1.60 M1D3371 490 2.69 387 372 1.42 M1D4 372 618 4.68 388 413 2.80 M2D1 373 3400.69 389 309 0.72 M2D2 374 356 0.85 390 314 1.17 M2D3 375 395 0.90 391342 1.27 M2D4 376 433 1.17 392 380 2.94 M3D1 377 295 0.81 393 271 0.94M3D2 378 313 1.27 394 292 0.93 M3D3 379 333 1.20 395 314 1.43 M3D4 380353 1.35 396 351 1.77 M4D1 381 255 1.12 397 260 0.74 M4D2 382 269 1.14398 267 0.93 M4D3 383 287 1.30 399 284 1.49 M4D4 384 316 1.67 400 2971.83

[0126] TABLE 21(A) S6740/55phr/0 RSS1 Sample Mw_(sol) Code No. (K) D (%)M1 1080 M2 837 M3 724 M4 532 M1D1 412 515 1.24 M1D2 413 556 1.32 M1D3414 633 1.41 M1D4 415 732 1.43 M2D1 416 433 0.86 M2D2 417 451 0.90 M2D3418 495 1.53 M2D4 419 542 2.15 M3D1 420 405 0.25 M3D2 421 418 0.50 M3D3422 447 0.75 M3D4 423 469 0.73 M4D1 424 371 0.21 M4D2 425 387 0.42 M4D3426 382 0.30 M4D4 427 396 0.56

[0127] TABLE 21(B) S6740/55phr/0 SMRCV Sample Mw_(sol) Code No. (K) D(%) M1 876 M2 754 M3 574 M4 444 M1D1 428 433 0.25 M1D2 429 441 0.36 M1D3430 467 0.34 M1D4 431 540 0.84 M2D1 432 399 0.35 M2D2 433 399 0.41 M2D3434 422 0.62 M2D4 435 469 0.44 M3D1 436 340 0.44 M3D2 437 363 0.81 M3D3438 377 0.89 M3D4 439 403 0.86 M4D1 440 363 0.65 M4D2 441 328 1.05 M4D3442 342 1.52 M4D4 443 360 1.99

[0128] TABLE 22(A) Regal 660/55phr/0 RSS1 SMRCV SMR10 Sample Mw_(sol)Sample Mw_(sol) Sample Mw_(sol) Code No. (K) D (%) No. (K) D (%) No. (K)D (%) M1 1110 836 746 M2 844 709 632 M3 609 584 492 M4 522 513 416 M1D1177 674 8.35 193 564 1.87 209 501 9.54 M1D2 178 792 7.89 194 611 2.50210 572 6.68 M1D3 179 891 8.53 195 708 3.08 211 681 7.37 M1D4 180 6767.46 196 671 2.31 212 594 7.18 M2D1 181 598 8.56 197 520 5.28 213 4632.82 M2D2 182 602 3.89 198 558 4.85 214 483 4.57 M2D3 183 697 6.40 199603 2.88 215 565 3.92 M2D4 184 659 5.71 200 541 4.25 216 550 5.68 M3D1185 473 2.03 201 486 2.79 217 395 2.13 M3D2 186 506 1.66 202 482 2.76218 393 1.98 M3D3 187 562 1.94 203 504 3.54 219 443 2.49 M3D4 188 5594.33 204 526 2.41 220 449 1.90 M4D1 189 401 2.18 205 415 3.16 221 3351.49 M4D2 190 426 1.72 206 418 2.92 222 345 1.71 M4D3 191 466 1.48 207446 2.80 223 363 1.78 M4D4 192 449 3.57 208 465 3.13 224 374 2.35

[0129] TABLE 22(B) Regal 660/45/0 Regal 660/65/0 Regal 660/65/10 RSS1RSS1 RSS1 Sample Mw_(sol) Sample Mw_(sol) Sample Mw_(sol) Code No. (K) D(%) No. (K) D (%) No. (K) D (%) M1 1245 1245 1245 M2 876 876 876 M3 625625 625 M4 482 482 482 M1D1 225 646 3.45 241 563 14.55 257 639 1.63 M1D2226 697 3.04 242 638 14.09 258 699 3.55 M1D3 227 762 7.70 243 691 13.64259 814 5.44 M1D4 228 830 6.75 244 790 11.26 260 764 11.25 M2D1 229 5744.79 245 469 5.88 261 572 2.77 M2D2 230 589 3.02 246 507 7.31 262 5804.39 M2D3 231 636 6.41 247 558 9.72 263 610 5.51 M2D4 232 675 6.55 248543 10.59 264 638 7.29 M3D1 233 471 2.66 249 420 5.48 265 474 4.10 M3D2234 481 5.17 250 426 6.97 266 485 5.72 M3D3 235 510 7.78 251 468 8.81267 502 6.24 M3D4 236 518 7.89 252 471 9.55 268 495 7.13 M4D1 237 3883.20 253 335 5.19 269 390 5.02 M4D2 238 392 5.65 254 344 6.06 270 3655.88 M4D3 239 397 5.14 255 344 5.59 271 410 7.45 M4D4 240 403 7.54 256361 8.54 272 388 7.59

[0130] TABLE 23(A) N234/55phr/0 RSS1 SMRCV SMR10 Sample Mw_(sol) SampleMw_(sol) Sample Mw_(sol) Code No. (K) D (%) No. (K) D (%) No. (K) D (%)M1 1060 845 743 M2 811 712 621 M3 595 577 445 M4 466 477 388 M1D1 273350 1.88 289 312 0.61 305 325 0.78 M1D2 274 476 3.40 290 317 0.64 306363 1.66 M1D3 275 459 2.70 291 361 1.03 307 400 1.89 M1D4 276 665 2.70292 419 1.56 308 459 1.73 M2D1 277 323 0.40 293 304 0.76 309 294 0.54M2D2 278 371 0.73 294 306 0.72 310 321 1.24 M2D3 279 398 0.74 295 3180.74 311 354 1.28 M2D4 280 464 1.42 296 357 1.30 312 363 1.39 M3D1 281278 0.47 297 260 0.53 313 260 0.69 M3D2 282 304 0.83 298 272 0.65 314268 0.48 M3D3 283 323 0.82 299 295 0.58 315 289 1.38 M3D4 284 360 1.06300 302 1.14 315 303 0.78 M4D1 285 251 0.61 301 244 0.53 317 236 1.00M4D2 286 266 0.51 302 253 0.81 318 239 0.77 M4D3 287 273 0.64 303 2660.62 319 257 0.72 M4D4 288 282 0.53 304 296 0.88 320 268 1.30

[0131] TABLE 23(B) N234/45/0 N234/65/0 N234/65/10 RSS1 RSS1 RSS1 SampleMw_(sol) Sample Mw_(sol) Sample Mw_(sol) Code No. (K) D (%) No. (K) D(%) No. (K) D (%) M1 1185 1185 1185 M2 828 828 828 M3 623 623 623 M4 462462 462 M1D1 321 507 7.33 337 336 3.44 353 395 5.51 M1D2 322 598 8.15338 458 5.09 354 478 7.68 M1D3 323 731 8.97 339 479 8.17 355 555 9.46M1D4 324 772 12.02 340 706 9.90 356 637 8.39 M2D1 325 486 3.48 341 2553.22 357 295 0.58 M2D2 326 479 5.44 342 288 3.34 358 352 1.23 M2D3 327527 5.51 343 295 4.65 359 394 1.35 M2D4 328 566 7.70 344 393 5.45 360449 2.37 M3D1 329 419 0.88 345 237 1.50 361 292 0.86 M3D2 330 423 1.24346 252 1.78 362 286 1.14 M3D3 331 431 2.55 347 270 2.88 363 313 2.19M3D4 332 458 4.03 348 304 3.92 364 340 2.51 M4D1 333 341 0.62 349 2261.18 365 265 0.83 M4D2 334 338 1.13 350 214 1.81 366 273 0.99 M4D3 335319 1.37 351 233 2.97 367 291 1.39 M4D4 336 354 2.06 352 258 3.83 368307 2.41

Preferred Embodiment Examples

[0132] Additional samples of elastomer composites in accordance with thepresent invention were prepared. Specifically, a series of naturalrubber elastomer composites no. 1-32 in accordance with the presentinvention was produced using apparatus and procedures generally inaccordance with those of Example A above. The elastomer compositescomprised natural rubber field latex from Malaysia with the propertiesshown in Table 24 below. The elastomer composites each further comprisedcarbon black with morphological properties (structure and surface area)of Regions I, II or III in FIG. 8. Specifically, the following carbonblacks were used: Regal® 660, N234, N326, N110, Regal® 250, N330, BlackPearl® 800, Sterling® 6740 and N351. The carbon black loadings rangedfrom 30 to 75 phr, and extender oil loadings were in an amount from 0 to20 phr. The production details for elastomer composite sample nos. 1-32are shown below in Table 25.

[0133] As noted above, the apparatus and procedures used to prepareelastomer composites no. 1-32 were generally in accordance with those ofExample A, including the masterbatch formulation additives shown inTable 2. A more detailed description of the apparatus and proceduresused for elastomer composites no. 1-32 is set forth below.

[0134] 1. Apparatus

[0135] Invention samples no. 1-32 were prepared using masterbatchproduction apparatus substantially in accordance with the inventionapparatus described above with reference to FIGS. 1, 4 and 7. Thediameter of the slurry nozzle tip (see item 167 in FIG. 7) and thelength of the land (see item 168 in FIG. 7) are given in Table 25 foreach of samples no. 1-32. The coagulum zone of the apparatus had fourzones of progressively larger diameter from the mixing zone to thedischarge end. The diameter and axial length of each of the four zones(the first zone being partly within the mix-head and partly within theextender sealed thereto) are set forth in Table 25. There were axiallyshort, faired interconnections between the zones.

[0136] 2. Carbon Black Slurry Preparation

[0137] Bags of carbon black were mixed with deionized water in a carbonblack slurry tank equipped with an agitator. The agitator broke thepellets into fragments to form a crude carbon black slurry. The carbonblack concentration (as weight percent) in the carbon black slurry foreach of the sample is given in Table 25. During operation, this slurrywas continually pumped by an air diaphragm pump to a grinder for initialdispersion. The slurry was then fed via an air diaphragm pump to acolloid mill which then fed into a progressing cavity pump to ahomogenizer, specifically, Microfluidizer Model M210 from MicrofluidicsInternational Corporation. The microfluidizer produced a finely groundslurry. The slurry flow rate from the microfluidizer to the mixing zonewas set by the microfluidizer pressure, the microfluidizer acting as ahigh-pressure positive displacement pump. Slurry flow rate was monitoredwith a Micromotion® mass flow meter. The pressure at which the carbonblack slurry was fed to the homogenizer and the homogenizer outputpressure (all pressures are psig) are set forth for each sample in Table25. From the homogenizer the carbon black slurry was fed to anaccumulator to reduce any fluctuation in slurry pressure at the slurrynozzle tip in the mixing zone. The slurry nozzle tip pressure and flowrate at which the slurry was fed to the mixing zone for each sample aregiven in Table 25.

[0138] 3. Latex Delivery

[0139] The latex was charged to a 55 gallon feed drum. Antioxidantemulsion was then added to the latex and mixed in prior to charging.Antioxidants were added consisting of tris nonyl phenyl phosphite (TNPP)and Santoflex® 134 (alkylaryl p-phenylene diamine mixture) in theamounts shown in Table 25. Each of the antioxidants was prepared as a 40wt. % emulsion using 4 parts potassium oleate per 100 parts antioxidantalong with potassium hydroxide to adjust the emulsion to a pH ofapproximately 10. Extender oil, if any, was added in the amount shown inTable 25. A peristaltic pump was used to move the latex from the feeddrum to the mixing zone of the coagulum reactor. The latex flow rate andvelocity are shown in Table 25. Latex flow was automatically meteredwith a Endress+Hauser mass flow meter. The desired carbon black loadingwas obtained by maintaining proper ratio of the latex feed rate to thecarbon black slurry feed rate.

[0140] 4. Carbon Black and Latex Mixing

[0141] The carbon black slurry and latex were mixed by entraining thelatex into the carbon black slurry. During entrainment, the carbon blackwas intimately mixed into the latex and the mixture coagulated. Soft,wet spongy “worms” of coagulum exited the coagulum reactor.

[0142] 5. Dewatering

[0143] The water content of the wet crumb discharged from the coagulumreactor is shown in Table 25. The wet crumb was dewatered with adewatering extruder (The French Oil Mill Machinery Company; 3½ in.diameter). In the extruder, the wet crumb was compressed and watersqueezed form the crumb and through a slotted barrel of the extruder.The final crumb moisture content is shown in Table 25 for each of theinvention samples.

[0144] 5. Drying and Cooling

[0145] The dewatered crumb dropped into a second extruder where it wasagain compressed and heated. Water was flashed off upon expulsion of thecrumb through the die plate of the extruder. Product exit temperatureand moisture content are shown in Table 25. The hot, dry crumb wasrapidly cooled (approximately 20 seconds) to about 100° F. by a forcedair vibrating conveyor. TABLE 24 Natural Rubber Latex PropertiesVolatile % Dry % Total Nitrogen Fatty Latex Type Source Additives RubberSolids % Ash ppm Acid Concentrate TITI Latex 0.35% NH₃ 60 62.0 0.15 0.290.022 SDN. BHD. ZnO, TMTD 0.1% HHS Field Latex RRIM^(a), 9/94 0.15%HNS^(c) 28.4 34.2 0.38 0.366 0.052 0.3% NH3, ZnO, TMTD^(b)

[0146] TABLE 25 Invention Sample Production Details Cabot ElastomerComposite Slurry Nozzle Tip MicroFluidizer Invention Carbon Black Oilloading Land length Inlet pressure Outlet pressure Sample No. Latex typeType Loading (phr) (phr) Dia. (in) (in) (psi) (psi) 1 field latex N33055 0 0.025 0.5 190 3000 2 field latex N330 55 0 0.039 1 300   0 3 fieldlatex N330 55 0 0.039 1 300   0 4 field latex REGAL 250 55 0 0.025 0.5180  3500 5 field latex REGAL 250 65 0 0.025 0.5 300 10000 6 field latexREGAL 250 75 0 0.025 0.5 200 13000 7 field latex REGAL 250 65 10 0.0250.5 250 12000 8 field latex BLACK PEARL 800 55 0 0.025 0.5 200  4000 9field latex N326 55 0 0.025 1 250  3000 10 field latex REGAL 860 55 00.025 1 — — 11 field latex REGAL 860 45 0 0.025 0.5 200 12500 12 fieldlatex REGAL 660 65 0 0.025 0.5 260 15000 13 field latex REGAL 660 65 100.025 0.5 200 12000 14 field latex N234 55 0 0.025 1 180  5500 15 fieldlatex N234 55 0 0.025 0.5 — 14500 16 field latex N234 55 0 0.025 0.5 —14500 17 field latex N234 55 0 0.025 0.5 — 14500 18 field latex N234 450 0.025 0.5 200 13000 19 field latex N234 65 0 0.025 0.5 220 13000 20field latex N234 65 10 0.025 0.5 300 14500 21 field latex N110 55 00.025 1 120  4500 22 latex concentrate N351 33 20 0.025 0.5 250 12500 23field latex STERLING 6740 55 0 0.025 0.5 250 12000 24 field latex N23448 5 0.023 0.5 250 11000 25 field latex N234 53 5 0.023 0.5 250 11000 26field latex N234 58 5 0.023 0.5 250 11000 27 field latex N234 63 5 0.0230.5 250 11000 28 field latex N234 68 5 0.023 0.5 250 11000 29 latexconcentrate N234 49 5 0.023 0.5 — — 30 latex concentrate N234 54 5 0.0230.5 — 11000 31 latex concentrate N234 63 5 0.023 0.5 — 11000 32 latexconcentrate N234 65 5 0.023 0.5 — 11000 Coagulum Zone CB SlurryInvention 1st portion 2nd portion 3rd portion 4th portion CB conc.Sample No. Dia. (in) Length (in) Dia. (in) Length (in) Dia. (in) Length(in) Dia. (in) Length (in) (% wt) 1 0.19 3.0 0.27 1.6 0.38 2.3 0.53 3.215.2 2 0.19 1.1 0.27 1.6 0.38 2.3 0.53 3.2 14.9 3 0.19 1.1 0.27 1.6 0.382.3 0.53 3.2 14.9 4 0.19 3.0 0.27 1.6 0.38 2.3 0.53 3.2 19.0 5 0.19 3.00.27 1.6 0.38 2.3 0.53 3.2 21.0 6 0.19 3.0 0.27 1.6 0.38 2.3 0.53 3.221.0 7 0.19 3.0 0.27 1.8 0.38 2.3 0.53 3.2 21.0 8 0.19 3.0 0.27 1.6 0.382.3 0.53 3.2 15.0 9 0.19 1.1 0.27 1.6 0.38 2.3 0.53 3.2 14.8 10 0.19 1.10.27 1.6 0.38 2.3 0.53 3.2 14.9 11 0.19 3.0 0.27 1.6 0.38 2.3 0.53 3.215.2 12 0.19 3.0 0.27 1.6 0.38 2.3 0.53 3.2 15.2 13 0.19 3.0 0.27 1.60.36 2.3 0.53 3.2 15.2 14 0.19 1.1 0.27 1.6 0.38 2.3 0.53 3.2 14.8 150.19 3.0 0.27 1.6 0.38 2.3 0.53 3.2 13.7 16 0.19 3.0 0.27 1.6 0.38 2.30.53 3.2 13.7 17 0.19 3.0 0.27 1.6 0.38 2.3 0.53 3.2 13.7 18 0.19 3.00.27 1.6 0.38 2.3 0.53 3.2 14.6 19 0.19 3.0 0.27 1.6 0.38 2.3 0.53 3.214.6 20 0.19 3.0 0.27 1.6 0.38 2.3 0.53 3.2 14.6 21 0.19 1.1 0.27 1.60.38 2.3 0.53 3.2 11.8 22 0.19 3.0 0.27 1.6 0.38 2.3 0.53 3.2 15.0 230.19 3.0 0.27 1.6 0.38 2.3 0.53 3.2 14.7 24 0.19 3.0 0.27 1.6 0.38 2.30.53 3.2 13.5 25 0.19 3.0 0.27 1.6 0.38 2.3 0.53 3.2 13.5 26 0.19 3.00.27 1.6 0.38 2.3 0.53 3.2 13.5 27 0.19 3.0 0.27 1.6 0.38 2.3 0.53 3.213.5 28 0.19 3.0 0.27 1.6 0.38 2.3 0.53 3.2 13.5 29 0.19 3.0 0.27 1.60.38 2.3 0.53 3.2 12.8 30 0.19 3.0 0.27 1.6 0.38 2.3 0.53 3.2 12.8 310.19 3.0 0.27 1.6 0.38 2.3 0.53 3.2 12.8 32 0.19 3.0 0.27 1.6 0.38 2.30.53 3.2 12.8 Slurry Nozzle Mixing Zone Invention Tip Pressure Slurryflow rate Slurry velocity Antioxidant Latex flow rate Latex velocitySample No. (psi) (lb/min) (ft/sec) TNPP (phr) Santoflex (phr) (lbs/min)(ft/sec) 1 1400 4.6 336 0.3 0.4 4.7 6.8 2  425 8.2 247 0.3 0.4 8.9 13.23  425 8.2 247 0.3 0.4 8.9 13.2 4 1500 4.8 344 0.3 0.4 6.7 9.7 5 15005.2 370 0.3 0.4 6.8 9.8 6 1575 5.2 370 0.3 0.4 5.9 8.5 7 1550 5.2 3700.3 0.4 6.9 10.0 8 1800 5.2 380 0.3 0.4 4.9 7.1 9  600 4.2 308 0.3 0.44.0 5.8 10 — 4.0 293 0.3 0.4 3.6 5.2 11 1500 5.1 373 0.3 0.4 7.0 10.1 121300 4.8 351 0.3 0.4 4.6 8.7 13 1375 4.9 358 0.3 0.4 4.8 6.9 14  900 5.3388 0.3 0.4 4.8 6.9 15 1400 5.7 420 0.3 0.4 5.4 7.8 16 1400 5.7 420 0.30.4 5.4 7.8 17 1400 5.7 420 0.3 0.4 5.4 7.8 18 1600 5.2 381 0.3 0.4 6.59.4 19 1650 5.3 388 0.3 0.4 4.5 6.5 20 1625 5.3 388 0.3 0.4 4.6 6.7 21 900 5.3 394 0.3 0.4 4.1 5.9 22 1550 5.1 373 0.3 0.4 5.1 7.8 23 1550 5.2381 0.3 0.4 5.7 8.3 24 2270 5.1 444 0.3 0.4 6.1 8.8 25 2250 5.1 444 0.30.4 5.5 7.9 26 2270 5.1 444 0.3 0.4 5.0 7.2 27 2280 5.1 444 0.3 0.4 4.66.6 28 — 5.1 444 0.3 0.4 4.2 6.1 29 2350 5.3 463 0.3 0.4 2.8 3.8 30 23805.3 463 0.3 0.4 2.3 3.4 31 2350 5.3 463 0.3 0.4 2.1 3.1 32 2420 5.3 4630.3 0.4 2.0 3.0 Dewatering Diving and Cooling Invention Initial crumbmoisture Final crumb moisture Product temperature Product moistureSample No. (%) (%) (°F.) (%) 1 77.6 6.5 312 0.3 2 78.7 — 450 0.2 3 78.77.8 400 0.2 4 74.9 — 350 0.3 5 76.2 7.9 310 0.2 6 76.4 11.4 — 0.2 7 75.68.8 335 0.3 8 77.7 6.5 310 0.2 9 77.9 8.9 345 0.2 10 77.8 — — 0.4 1178.7 9.7 285 0.5 12 79.7 — 335 0.2 13 79.1 — — 0.9 14 77.9 8.4 330 0.115 79.2 — oven dried — 16 79.2 10.3 oven dried — 17 79.2 11.2 oven dried— 18 79.0 15.0 370 0.4 19 80.0 3.6 325 0.3 20 79.5 9.4 345 0.5 21 80.59.5 350 0.2 22 65.1 9.1 280 0.3 23 78.1 6 330 0.8 24 77.4 — 380 0.3 2577.8 — 390 0.4 26 78.1 — 400 0.7 27 78.4 — 410 0.4 28 78.7 — 420 1.1 2971.2 — 400 0.6 30 72.3 — 420 0.4 31 73.3 — 400-450 0.9 32 74.1 — 400-4500.2

[0147] It should be noted that samples 2 and 3 were produced withapproximately no outlet pressure at the Microfluidizer outlet, etc., todetermine macro-dispersion under adverse process conditions.

[0148] The excellent carbon black dispersion in the resultantmasterbatches is demonstrated by their macro-dispersion quality andmolecular weight of the sol portion MW_(sol). Table 26 below shows theMW_(sol) and macro-dispersion values for invention samples 1-32, alongwith the carbon black and oil (if any) used in each of the samples. Thecarbon black loading and oil loading are shown as phr values in Table26. TABLE 26 Sol Molecular Weight and Undispersed Area of IntentionSamples Invention Sample No. CB/Loading/Oil Mw_(sol) (K) D (%)  1N330/55/0 305 0.26  2 N330/55/0 726 0.54  3 N330/55/0 544 0.40  4R250/55/0 876 0.08  5 R250/65/0 670 0.16  6 R250/75/0 655 0.03  7R250/65/10 519 0.02  8 BP800/55/0 394 0.14  9 N326/55/0 666 0.20 10R660/55/0 678 0.12 11 R660/45/0 733 0.05 12 R660/65/0 568 0.04 13R660/65/10 607 0.02 14 N234/55/0 433 0.15 15 N234/55/0 1000  0.10 16N234/55/0 500 0.15 17 N234/55/0 550 0.10 15 N234/46/0 495 0.17 19N234/65/0 359 0.20 20 N234/65/10 350 0.11 21 N110/55/0 612 0.17 22N351/33/20 800 0.10 23 S6740/55/0 630 0.10 24 N234/48/5 569 0.05 25N234/53/5 485 0.12 26 N234/58/5 447 0.12 27 N234/63/5 403 0.13 28N234/68/5 378 0.16 29 N234/49/5 618 0.12 30 N234/54/5 482 0.16 31N234/63/5 390 0.17 32 N234/65/5 325 0.20

[0149] The results for all invention samples having carbon black loadingof 55 phr are shown in the semi-log slot of FIG. 9 along withmacro-dispersion and MW_(sol) values for a corresponding series of theabove described natural rubber control samples produced by dry mixingtechniques. At least one data point for an invention sample comprising55 phr loading of each carbon black is shown in FIG. 9, along with allof the control samples having carbon black loading of 55 phr. (Controlsamples 401 to 412, also shown in FIG. 9, used 33 phr N351 carbon blackand 20 parts extender oil.) It can be seen in Table 26 and in FIG. 9that the invention samples have excellent macro-dispersion.Specifically, the invention samples have D(%) values generally below0.2%, even at MW_(sol) values above 0.85×10⁶ whereas the control samplesnever achieve such excellent macro-dispersion at any MW_(sol). Thus, thedata shown in FIG. 9 clearly reveals that the macro-dispersion qualityof the novel elastomer composites over a wide range of MW_(sol) valuesis significantly superior to that achievable using comparableingredients in prior-known dry mixing methods. The symbols used for thevarious data points shown in FIG. 9 and those used in subsequentlydiscussed FIGS. 10-25 are explained in the legends below. FIG. 9Dispersion Quality and MW Sol of NR Masterbatches

control samples 177 to 224 ▴ control samples 273 to 320

control samples 145 to 176 Δ control samples 369 to 400 ◯ controlsamples 33 to 64 X control samples 1 to 32  control samples 113 to 144⋄ control samples 412 to 443 ♦ control samples 401 to 412 ▪ inventionsamples

[0150] FIG. 10 Dispersion Quality and MW Sol at NR Masterbatches (RegionI)

control samples 177 to 224

Invention sample 10

control samples 145 to 176

invention sample 9 ◯ control samples 33 to 64 □ invention sample 4 Xcontrol samples 1 to 32

invention sample 1  control samples 113 to 144 ▪ invention sample 8

[0151] FIG. 11 Dispersion Quality and MW Sol of NR Masterbatches (RegionII) ▴ control samples 273 to 320 ▪ invention sample 14 Δ control samples369 to 400 □ invention sample 21

[0152] FIG. 12 Dispersion Quality and MW Sol of NR Masterbatches (RegionIII) ♦ control samples 401 to 412 ▪ invention sample 22 ⋄ controlsamples 412 to 443 □ Invention sample 23

[0153] FIG. 13 Dispersion Quality and MW Sot of NR Masterbatches (N330Carbon Black, 55 phr)  control samples 1 to 32 ▪ invention samples 1 to3

[0154] FIG. 14 Dispersion Quality and MW Sol of NR Masterbatches (REGAL250 Carbon Black)  control samples 33 to 64 ▪ invention sample 4 ◯control sample 65 to 80 □ invention sample 5 ⋄ control samples 81 to 96Δ invention sample 6 ♦ control samples 97 to 112 ▴ Invention sample 7

[0155] FIG. 15 Dispersion Quality and MW Sol of NR Masterbatches (BLACKPEARL 800 Carbon Black, 55 phr)  control samples 113 to 144 ▪ inventionsample 8

[0156] FIG. 16 Dispersion Quality and MW Sol of NR Masterbatches (N326Carbon Black, 55 phr)  control samples 145 to 176 ▪ invention sample 9

[0157] FIG. 17 Dispersion Quality and MW sol of NR Masterbatches (REGAL660 Carbon Black)  control samples 177 to 224 ▪ invention sample 10 ◯control samples 225 to 240 □ invention sample 11 ⋄ control samples 241to 256 Δ invention sample 12 ♦ control samples 257 to 272 ▴ inventionsample 13

[0158] Dispersion Quality and MW sol of NR Masterbatches (N234 CarbonBlack)  control samples 273 to 320 ▪ invention samples 14 to 17 ∘control samples 337 to 352 □ invention sample 19 ⋄ control samples 321to 336 Δ invention sample 18 ♦ control samples 353 to 368 ▴ inventionsample 20

[0159] Dispersion Quality and MW Sol of NR Masterbatches (N110 CarbonBlack, 55 phr)  control samples 389 to 400 ▪ invention sample 21

[0160] Dispersion Quality and MW sol of NR Masterbatch (N351 CarbonBlack, 33 phr)  control samples 401 to 412 ▪ invention sample 22

[0161] Dispersion Quality and MW Sol of NR Masterbatches (STERLING 6740Carbon Black, 55 phr)  control samples 412 to 443 ▪ invention sample 23

[0162] MW sol Effect on Crack Growth Rate (NR Compounds Containing N234Carbon Black @ 55 phr Loading)  control samples 273 to 288

invention sample 16

[0163] MW sol Effect on Crack Growth Rate (NR Compounds Containing N326Carbon Black @ 55 phr Loading)  control samples 145 to 160 ∘ inventionsample 9

[0164] MW sol Effect on Crack Growth Rate (NR Compounds Containing REGAL660 Carbon Black @ 55 phr Loading)  control samples 177 to 192 □invention sample 10

[0165] Max. Tan δ (Strain Sweep @ 60 C.) of NR Compounds Containing N234Black at Different Loadings  invention samples 24 to 28 ∘ inventionsamples 29 to 32

control sample 444 to 450

[0166] Macro-dispersion Quality and MW of Sol Portion of NR MasterbatchContaining Dual Phase (Carbon Black/Silica) Aggregates  control samples451 to 458 ▪ invention sample 33 ∘ control samples 459 to 466 □invention sample 34

[0167] Macro-dispersion Quality and MW of Sol Portion of NR MasterbatchContaining Blend of Carbon Black and Silica  control samples 491 to 498▪ invention sample 38 ∘ control samples 483 to 490 □ invention sample 37

control samples 475 to 482

invention sample 36  control samples 467 to 474 ▪ invention sample 35

[0168] The macro-dispersion values for the elastomer composites of theinvention shown in FIG. 9 are described by the following equations:

D(%)<0.2%  (1)

[0169] when MW_(sol) is less than 0.45×10⁶; and

log(D)<log(0.2)+2.0×[MW _(sol)−(0.45×10⁶)]×10⁻⁶  (2)

[0170] when 0.45×10⁶<MW_(sol)<1.1×10⁶.

[0171] It will be recognized from the discussion above, thatmacro-dispersion D (%) in the above equation (1) is the percentundispersed area measured for defects greater than 10 microns. It can beseen in FIG. 9 that D(%) equal to 0.2% is the threshold macro-dispersionquality for all carbon blacks in Regions I, II and III for naturalrubber dry masterbatches. That is, none of the dry masticatedmasterbatches achieved macro-dispersion quality of 0.2% at any MW_(sol),even after mixing sufficiently to degrade MW_(sol) below 0.45×10⁶, asdescribed by equation (1) above. When the MW_(sol) of the drymasterbatch control samples shown in FIG. 9 is between 0.45×10⁶ and1.1×10⁶, the dispersion quality is even poorer while, in contrast, thedispersion quality of the invention samples having MW_(sol) in thatrange remains excellent. None of the preferred embodiments shown in FIG.9 having MW_(sol) between 0.45×10⁶ and 1.1×10⁶ exceeds the preferredmacro-dispersion limit of 0.2%. In that regard, it should be understoodthat the data points for preferred embodiments which are seen in FIG. 9(and in other Figures discussed below) to lie on the X axis (i.e., atD(%) value of 0.1%) may have macro-dispersion quality of 0.1% or an evenbetter (i.e., lower) D(%) value.

[0172] Region I Carbon Black Samples

[0173] Invention samples comprising carbon blacks having morphologicalproperties (i.e., structures and surface area) of Region I in FIG. 8,and corresponding control samples described above made with such RegionI carbon blacks, are compared in the semi-log plot of FIG. 10.Specifically, FIG. 10 shows the macro-dispersion values and MW_(sol)values of the invention samples and corresponding control samplescomprising the carbon blacks Regal® 660, N326, Regal® 250, N330, andBlack Pearl® 800, at carbon black loading ranging from 30 phr to 75 phrand extender oil loading ranging from 0 phr to 20 phr. Excellent carbonblack dispersion is seen in FIG. 10 for all of the invention samples,representing preferred embodiments of elastomer composites in accordancewith the present disclosure. All of the invention samples advantageouslyare below line 101 in FIG. 10, whereas all of the control samples havepoorer dispersion, being above line 101. In fact, the preferredembodiments shown in FIG. 10, even through comprising carbon blacks fromRegion I, the most difficult to disperse, all fall below a D(%) value of0.3%. The most preferred embodiments all have a D(%) value not exceeding0.2% even at an MW_(sol) value advantageously exceeding 0.7×10⁶. Thedata shown in FIG. 10 clearly reveals that the macro-dispersion qualityof the novel elastomer composites disclosed here comprising Region Icarbon blacks, over a wide range of MW_(sol) values, is significantlysuperior to that achievable using comparable ingredients by prior drymastication mixing methods. The macro-dispersion values for theelastomer composites of the invention shown in FIG. 10 are described bythe following equations:

D(%)<1.0%  (3)

[0174] when MW_(sol) is less than 0.7×10⁶; and

log D<log(1.0)+2.5×[MW _(sol)−(0.7×10⁶)]×10⁻⁶  (4)

[0175] when 0.7×10⁶<MW_(sol)<1.1×10⁶

[0176] It will be recognized that D (%) is the percent undispersed areameasured for defects greater than 10 microns and 1% is the thresholdmacro-dispersion quality for all carbon blacks in Region I for naturalrubber masterbatches in accordance with the present invention. That is,none of the dry masticated masterbatches achieved macro-dispersionquality of 1.0% or better at any MW_(sol), even after dry mixingsufficiently to degrade MW_(sol) below 0.7×10⁶, as described by Equation(3) above. When the MW_(sol) of the dry masterbatch control samplesshown in FIG. 10 is between 0.7×10⁶ and 1.1×10⁶, the dispersion qualityis even poorer. In contrast, the dispersion quality of the inventionsamples having MW_(sol) in that range remains excellent. The preferredembodiment shown in FIG. 10 having MW_(sol) between 0.7×10⁶ and 1.1×10⁶falls well below the preferred macro-dispersion limit of 0.2%. It can beseen that the elastomer composites of the invention comprising carbonblacks from Region I provide heretofore unachieved balance betweenmacro-dispersion quality and MW_(sol).

[0177] Region II Carbon Black Samples

[0178] Invention samples comprising carbon blacks having morphologicalproperties (i.e., structure and surface area) of Region II in FIG. 8,and corresponding control samples described above made with such RegionII carbon blacks are compared in the semi-log plot of FIG. 11.Specifically, FIG. 11 shows the macro-dispersion values and MW_(sol)values of the invention samples and corresponding control samplescomprising the carbon blacks N234 and N110 at carbon black loadingranging from 40 phr to 70 phr and extender oil loading ranging from 0phr to 10 phr. Excellent carbon black dispersion is seen in FIG. 11 forall of the invention samples, representing preferred embodiments ofelastomer composites in accordance with the present disclosure. Theinvention samples advantageously are below line 111 in FIG. 11, whereasall of the control samples have poorer dispersion, being above line 111.In fact, the preferred embodiments shown in FIG. 11 comprising carbonblacks from Region II fall below a D(%) value of 0.3%. Most preferredembodiments have a D(%) value not exceeding 0.2% at any MW_(sol) value.The data shown in FIG. 11 clearly reveal that the macro-dispersionquality of the novel elastomer composites disclosed here comprisingRegion II carbon blacks, over a wide range of MW_(sol) values, issignificantly superior to that achievable using comparable ingredientsin prior dry mixing methods. The macro-dispersion values for theelastomer composites of the invention shown in FIG. 11 are described bythe following equations:

D(%)<0.3%  (5)

[0179] when MW_(sol) is less than 0.35×10⁶; and

log D<log(0.3)+2.8×[MW _(sol)−(0.35×10⁶)]×10−6  (6)

[0180] when 0.35×10⁶<MW_(sol)<1.1×10⁶.

[0181] It will be recognized that D (%) of 0.30% is the thresholdmacro-dispersion quality for all carbon blacks in Region II for naturalrubber masterbatches in accordance with the present invention, and0.35×10⁶ is the threshold MW_(sol) value. That is, none of the drymasterbatches achieved macro-dispersion quality of 0.30% or better atany MW_(sol) even after dry mixing sufficiently to degrade MW_(sol)below 0.35×10⁶, as described by Equation (5) above. When the MW_(sol) ofthe dry masterbatch control samples shown in FIG. 11 is between 0.35×10⁶and 1.1×10⁶, the dispersion quality is even poorer. In contrast, thedispersion quality of the invention samples having MW_(sol) in thatrange remains excellent. The preferred embodiments shown in FIG. 11having MW_(sol) between 0.35×10⁶ and 1.1×10⁶ fall well below thepreferred macro-dispersion limit of 0.2%. It can be seen that theelastomer composites of the invention comprising carbon blacks fromRegion II provide heretofore unachieved balance between macro-dispersionquality and MW_(sol).

[0182] Region III Carbon Black Samples

[0183] Invention samples comprising carbon blacks having morphologicalproperties (i.e., structures and surface area) of Region III in FIG. 8,and corresponding control samples described above made with such RegionIII carbon blacks are compared in the semi-log plot of FIG. 12.Specifically, FIG. 12 shows the macro-dispersion values and MW_(sol)values of the invention samples and corresponding control samplescomprising the carbon blacks N351 and Sterling 6740, at carbon blackloading ranging from 30 phr to 70 phr and extender oil loading rangingfrom 0 phr to 20 phr. Excellent carbon black dispersion is seen in FIG.12 for all of the invention samples, representing preferred embodimentsof elastomer composites in accordance with the present disclosure. Allof the invention samples advantageously are below line 121 in FIG. 12,whereas all of the control samples have poorer dispersion, being aboveline 121. In fact, the preferred embodiments shown in FIG. 12,comprising carbon blacks from Region III, fall at or below a D(%) valueof 0.1%, even at an MW_(sol) value advantageously exceeding 0.3×10⁶ andeven 0.7×10⁶. The data shown in FIG. 12 clearly reveals that themacro-dispersion quality of the novel elastomer composites disclosedhere comprising Region III carbon black, over a wide range of MW_(sol)values, is significantly superior to that achievable using comparableingredients in prior dry mixing methods. The macro-dispersion values forthe elastomer composites of the invention shown in FIG. 12 are describedby the following equations:

D(%)<0.1%  (7)

[0184] when MW_(sol) is less than 0.35×10⁶; and

log D<log(0.1)+2.0×[MW _(sol)−(0.30×10⁶)×10⁻⁶]  (8)

[0185] when 0.30×10⁶<MW_(sol)<1.1×10⁶.

[0186] It will be recognized that D (%) of 0.1% is the thresholdmacro-dispersion quality for all carbon blacks in Region III for naturalrubber masterbatches in accordance with the present invention, and0.3×10⁶ is the threshold MW_(sol) value. That is, none of the drymasterbatches achieved macro-dispersion quality of 0.1% at any MW_(sol),even after dry mixing sufficiently to degrade MW_(sol) below 0.35×10⁶,as described by Equation (7) above. When the MW_(sol) of the drymasterbatch control samples shown in FIG. 12 is between 0.30×10⁶ and1.1×10⁶, the dispersion quality is even poorer. In contrast, thedispersion quality of the invention samples having MW_(sol) in thatrange remains excellent. The preferred embodiments shown in FIG. 12having MW_(sol) between 0.30×10⁶ and 1.1×10⁶ fall well below thepreferred macro-dispersion limit of 0.2%, and, in fact, are at or belowD(%) value of 0.1%. It can be seen that the elastomer composites of thepresent invention comprising carbon blacks from Region III provideheretofore unachieved balance between macro-dispersion quality andMW_(sol).

[0187] Additional Sample Comparisons

[0188] The macro-dispersion values for the invention samples are showngraphically in the semi-long plots of FIGS. 13 through 21, as a functionof their MW_(sol) values, as in FIGS. 8 through 12 discussed above. Morespecifically, in FIGS. 13 through 21 all invention samples describedabove comprising a particular carbon black (being limited to those of aspecific carbon black loading when so indicated) are shown together in asingle semi-log plot together with the corresponding control samples.(See the legends above giving the reference numbers of the inventionsamples and control samples included in each figure.) Thus, FIG. 13shows the dispersion quality and MW_(sol) of invention and controlsamples described above comprising 55 phr N330 carbon black. The datashown in FIG. 13 clearly reveals that the macro-dispersion quality ofthe novel elastomer composites of the invention, comprising N330 carbonblack, over a wide range of MW_(sol) values, is significantly superiorto that of the control samples. Macro-dispersion for elastomercomposites of the invention comprising N330 carbon black, as shown inFIG. 13 is described by the following equations:

D(%)<1%  (9)

[0189] when MW_(sol)<0.6×10⁶; and

log(D)<log(1)+2.5×[MW _(sol)−(0.6×10⁶)]×10⁻⁶  (10)

[0190] when 0.6×10⁶<MW_(sol)<1.1×10⁶.

[0191] None of the dry masticated masterbatches achievedmacro-dispersion quality of 1.0% at any MW_(sol), even after dry mixingsufficiently to degrade MW_(sol) below 0.6×10⁶ (see Equation 9, above).In control samples comprising 55 phr N330 carbon black in which theMW_(sol) was maintained between 0.6×10⁶ and 1.1×10⁶, the D(%) value iseven higher, such as more than 4% undispersed area.

[0192]FIG. 14 shows the dispersion quality and MW_(sol) of the inventionand control samples described above comprising REGAL® 250 carbon black.Selected invention and control samples shown in FIG. 14 comprised oil,as set forth above. The data shown in FIG. 14 clearly reveals that themacro-dispersion quality of the novel elastomer composites of theinvention comprising REGAL® 250 carbon black, over a wide range ofMW_(sol) values, is significantly superior to that of the controlsamples. The macro-dispersion values for the elastomer composites of theinvention comprising REGAL® 250 carbon black, as shown in FIG. 14 aredescribed by the following equations:

D(%)<1%  (9)

[0193] when MW_(sol)<0.6×10⁶; and

log(D)<log(1)+2.5×[MW _(sol)−(0.6×10⁶)]×10 ⁻⁶  (10)

[0194] when 0.6×10⁶<MW_(sol)<1.1×10⁶.

[0195] None of the control samples achieved macro-dispersion quality of1.0% or better at any MW_(sol), even after dry mixing sufficiently todegrade MW_(sol) below 0.6×10⁶. In contrast, elastomer composites of theinvention comprising Regal® 250 carbon black and having MW_(sol) above0.6×10⁶ have excellent macro-dispersion, such as D(%) less than 0.2%.Compound properties and performance characteristics for the inventionand control samples shown in FIG. 14, comprising REGAL® 250 carbonblack, are set forth in Table 27 below. It can be seen that inventionsample No. 4 has exceptionally good resistance to crack growth, asindicated by its very low crack growth rate value of only 0.92cm/million cycles. In fact, the invention sample is far superior to thecorresponding control samples. This is believed to be due largely to thebetter MW_(sol) and macro-dispersion of carbon black in the inventionsample, as discussed above. TABLE 27 Compound Properties of NR CompoundsContaining REGAL 250 Carbon Black at 55 phr Loading Mooney E100 E300Tensile EB Sample No. ML(1 + 4)@100C Hardness (psi) (psi) (psi) (%)control 33 60.63 55.35 181.26  999.82 4090.24 675.0 control 34 73.5857.80 235.14 1293.88 3978.24 595.0 control 35 81.49 58.65 243.66 1265.284103.41 613.0 control 36 84.04 59.95 244.23 1215.87 3960.32 614.0control 37 57.35 56.75 218.70 1259.99 4119.85 502.0 control 38 60.1057.05 216.75 1206.60 4023.65 620.0 control 39 68.28 57.25 225.44 1256.234134.06 621.0 control 40 77.40 59.10 255.15 1330.87 4059.01 597.0control 41 44.40 56.25 216.00 1214.78 4038.68 618.0 control 42 47.9656.50 214.53 1202.93 3944.05 613.0 control 43 49.84 57.05 221.26 1229.074018.24 611.0 control 44 50.10 56.60 210.50 1140.90 4058.33 638.0control 45 36.82 52.90 177.47  982.86 3790.56 533.0 control 46 38.2354.50 198.63 1111.04 3860.56 629.0 control 47 35.35 54.60 199.03 1110.003871.49 505.0 control 48 40.58 55.50 204.52 1139.94 3961.06 632.0invention 4 71.97 57.00 218.18 1230.30 4036.30 611.0 Crack Growth RateAbrasion loss Tan δ Tan δ Sample No. Rebound (cm/million cycles) (g) @0° C. @ 60° C. control 33 64.50 2.00 0.191 0.167 0.091 control 34 64.551.83 0.182 0.155 0.083 control 35 63.75 2.38 0.192 0.150 0.091 control36 63.30 1.42 0.180 0.162 0.091 control 37 64.65 3.00 0.168 0.178 0.100control 38 63.45 2.99 0.163 0.184 0.099 control 39 63.90 2.17 0.1860.170 0.092 control 40 62.30 1.69 0.182 0.175 0.093 control 41 64.202.84 0.190 0.189 0.102 control 42 64.20 3.24 0.182 0.168 0.103 control43 64.50 3.52 0.177 0.183 0.101 control 44 63.90 3.50 0.179 0.185 0.104control 45 63.80 3.86 0.199 0.197 0.104 control 46 64.30 3.94 0.1910.184 0.107 control 47 64.35 3.81 0.192 0.106 control 48 63.65 3.460.180 0.182 0.110 invention 4 64.70 0.92 0.190 0.148 0.096

[0196]FIG. 15 shows the dispersion quality and MW_(sol) of the inventionand control samples described above comprising BLACK PEARL® 800 carbonblack at 55 phr loading. The data shown in FIG. 15 clearly reveals thatthe macro-dispersion quality of the novel elastomer composites of theinvention comprising Black Pearly 800 carbon black, is significantlysuperior to that of the control samples. The macro-dispersion values forelastomer composites of the invention comprising Black Pearl® 800 carbonblack, as shown in FIG. 15, are described by the following equations:

D(%)<1.5%  (11)

[0197] when MW_(sol)<0.65×10⁶; and

log(D)<log(1.5)+2.5×[MW _(sol)−(0.65×10⁶)]×10⁻⁶  (12)

[0198] when 0.65×10⁶<MW_(sol)<1.1×10⁶.

[0199] None of the control samples achieved macro-dispersion quality of1.0% or better at any MW_(sol), even after dry mixing sufficiently todegrade MW_(sol) below 0.65×10⁶. In contrast, elastomer composites ofthe invention comprising Black Pearl® 800 carbon black and havingMW_(sol) above 0.65×10⁶ have excellent macro-dispersion, such as D(%)less than 0.2%. Compound properties and performance characteristics forthe invention and control samples shown in FIG. 15, comprising BlackPearl® 800 carbon black, are set forth in Table 28 below. It can be seenthat invention sample No. 8 has exceptionally good resistance to crackgrowth, as indicated by its very low crack growth rate value of only0.27 cm/million cycles. In fact, the invention samples are far superiorto the corresponding control samples. This is believed to be due largelyto the better MW_(sol) and macro-dispersion of carbon black in theinvention sample, as discussed above. TABLE 28 Compound Properties of NRCompounds Containing BLACK PEARL 800 Carbon Black at 55 phr LoadingMooney E100 E300 Tensile EB Sample No. ML(1 + 4)@100C Hardness (psi)(psi) (psi) (%) control 113 110.5 66.4 345.0 1333.0 3878.0 598 control114 109.0 67.3 367.0 1427.0 4033.0 606 control 115 106.4 67.2 363.01311.0 3896.0 610 control 116 105.7 69.0 322.0 1202.0 3856.0 626 control117 110.6 67.1 316.0 1400.0 4180.0 616 control 118 118.9 67.1 310.01395.0 3967.0 607 control 119 111.9 67.7 309.0 1323.0 4149.0 634 control120 110.6 67.6 373.0 1188.0 4199.0 653 control 121 114.7 66.3 287.01262.0 4329.0 667 control 122 110.6 65.8 288.0 1223.0 4217.0 659 control123 115.0 67.5 280.0 1282.0 4071.0 624 control 124 116.5 66.5 309.01388.0 4166.0 623 control 125 113.4 65.4 281.0 1274.0 3978.0 631 control126 101.4 66.8 280.0 1222.0 4206.0 656 control 127 105.5 66.4 282.01150.0 4167.0 670 control 128 110.7 66.8 292.0 1301.0 4209.0 643invention 8 131.3 62.5 227.0 1291.0 3418.0 532 Crack Growth RateAbrasion loss Tan δ Tan δ Sample No. Rebound (cm/million cycles) (g) @0° C. @ 60° C. control 113 44.7 3.14 0.148 0.281 0.184 control 114 45.02.72 0.125 0.274 0.185 control 115 47.0 2.54 0.163 0.233 0.171 control116 46.6 2.41 0.194 0.244 0.163 control 117 40.9 4.56 0.086 0.327 0.214control 118 41.8 2.80 0.112 0.335 0.225 control 119 41.7 4.33 0.0910.321 0.216 control 120 42.1 3.89 0.095 0.301 0.207 control 121 39.23.38 0.075 0.312 0.256 control 122 38.7 4.58 0.108 0.344 0.236 control123 40.2 4.79 0.103 0.329 0.232 control 124 41.7 3.78 0.102 0.321 0.209control 125 38.9 3.40 0.076 0.352 0.248 control 126 38.1 5.57 0.0700.355 0.241 control 127 38.2 4.79 0.073 0.346 0.254 control 128 39.43.40 0.113 0.357 0.23  invention 8 44.8 0.27 0.130 0.297 0.199

[0200]FIG. 16 shows the dispersion quality and MW_(sol) of the inventionand control samples described above comprising N326 carbon black at 55phr loading. The data shown in FIG. 16 clearly reveals that themacro-dispersion quality of the novel elastomer composites of theinvention comprising N326 carbon black is significantly superior to thatof the control samples. The macro-dispersion values for the elastomercomposites of the invention comprising N326 carbon black, as shown inFIG. 16, are described by the following equations:

D(%)<1%  (13)

[0201] when M_(sol)<0.7×10⁶; and

log(D)<log(1)+2.5×[MW _(sol)−(0.7×10⁶)]×10⁻⁶  (14)

[0202] when 0.7×10⁶<MW_(sol)<1.1×10⁶.

[0203] None of the control samples achieved macro-dispersion quality of1.0% or better at any MW_(sol), even after dry mixing sufficiently todegrade MW_(sol) below 0.7×10⁶. In contrast, elastomer composites of theinvention comprising N326 carbon black and having MW_(sol) above 0.7×10⁶have excellent macro-dispersion, such as D(%) not greater than 0.2%.Compound properties and performance characteristics for the inventionand control samples shown in FIG. 16, comprising N326 carbon black areset forth in Table 29 below. It can be seen that invention sample No. 9has exceptionally good resistance to crack growth, as indicated by itsvery low crack growth rate value of only 0.77 cm/million cycles. Infact, the invention sample is far superior to the corresponding controlsamples. This is believed to be due largely to the better MW_(sol) andmacro-dispersion of carbon black in the invention sample, as discussedabove. TABLE 29 Compound Properties of NR Compounds Containing N326Carbon Black at 55 phr Loading Mooney E100 E300 Tensile EB Sample No.ML(1 + 4)@100C Hardness (psi) (psi) (psi) (%) control 145 64.8 60.5 2891713 3921 548 control 146 88.2 62.4 340 1802 4094 553 control 147 91.763.3 391 1917 3991 528 control 148 96.8 64.3 326 1684 4045 572 control149 62.4 61.5 310 1783 4029 552 control 150 67.7 62.8 326 1865 4055 551control 151 76.5 60.6 287 1641 4015 575 control 152 79.4 63.6 329 17203980 559 control 153 57.2 60.1 282 1623 3968 579 control 154 57.2 62.8354 1889 3879 525 control 155 57.3 62.2 323 1763 3975 556 control 15660.1 61.9 310 1667 3918 564 control 157 45.1 61.2 328 1748 3768 533control 158 50.1 60.8 315 1740 3817 546 control 159 53.2 61.3 306 16753886 563 control 160 50.5 62.6 331 1752 3864 549 invention 9 77.8 60.9277 1563 4167 593 Crack Growth Rate Abrasion loss Tan δ Tan δ Sample No.Rebound (cm/million cycles) (g) @ 0° C. @ 60° C. control 145 57.8 2.840.0952 0.225 0.129 control 146 58.1 2.52 0.0887 0.217 0.126 control 14757.6 2.03 0.0946 0.205 0.123 control 148 58.3 1.63 0.0927 0.221 0.129control 149 57.2 3.39 0.0827 0.234 0.142 control 150 56.8 2.77 0.08660.234 0.150 control 151 55.6 2.81 0.0933 0.241 0.149 control 152 54.52.79 0.0857 0.249 0.155 control 153 55.4 3.12 0.0911 0.258 0.170 control154 56.0 3.35 0.0858 0.241 0.147 control 155 55.4 3.63 0.0811 0.2540.152 control 156 54.9 3.55 0.0906 0.261 0.153 control 157 55.5 3.020.0931 0.254 0.149 control 158 55.4 3.81 0.0914 0.249 0.150 control 15954.9 3.23 0.0933 0.240 0.158 control 160 55.2 3.19 0.0942 0.246 0.163invention 9 58.4 0.77 0.0939 0.225 0.136

[0204]FIG. 17 shows the dispersion quality and MW_(sol) of the inventionand control samples described above comprising REGAL (trademark) 660carbon black. Selected invention and control samples shown in FIG. 17comprised oil, as set forth above. The data shown in FIG. 17 clearlyreveals that the macro-dispersion quality of the novel elastomercomposites of the invention comprising REGAL M® 660 carbon black, over awide range of MW_(sol) values, is significantly superior to that of thecontrol samples. The macro-dispersion values for the elastomercomposites of the invention comprising REGAL® 660 carbon black, as shownin FIG. 17 are described by the following equations:

D(%)<1%  (15)

[0205] when MW_(sol)<0.6×10⁶; and

log(D)<log(1)+2.5×[MW _(sol)−(0.6×10⁶)]×10⁻⁶  (16)

[0206] when 0.6×10⁶<MW_(sol)<1.1×10⁶.

[0207] None of the control samples achieved macro-dispersion quality of1.0% or better at any MW_(sol), even after dry mixing sufficiently todegrade MW_(sol) below 0.6×10⁶ In contrast, elastomer composites of theinvention comprising Regal® 660 carbon black and having MW_(sol) above0.6×10⁶ have excellent macro-dispersion, such as D(%) less than 0.2%.Compound properties and performance characteristics for the inventionsample No. 10 and various control samples shown in FIG. 17, comprisingRegal® 660 carbon black, are set forth in Table 30 below. It can be seenthat invention sample No. 10 has exceptionally good resistance to crackgrowth, as indicated by its very low crack growth rate value of only0.69 cm/million cycles. In fact, the invention samples are far superiorto the corresponding control samples. This is believed to be due largelyto the better MW_(sol) and macro-dispersion of carbon black in theinvention sample, as discussed above. TABLE 30 Compound Properties of NRCompounds Containing REGAL 660 Carbon Black at 55 phr Loading MooneyE100 E300 Tensile EB Sample No. ML(1 + 4)@100C Hardness (psi) (psi)(psi) (%) control 177 61.0 213 942 702 control 178 87.6 63.2 232 9434002 694 control 179 87.1 64.9 285 1134 4016 644 control 180 85.6 64.0271 1198 4058 618 control 181 80.1 61.0 206 945 4098 661 control 18293.4 59.0 192 835 3924 733 control 183 89.0 61.0 215 920 4134 698control 184 83.4 62.4 223 996 4236 694 control 185 70.1 60.0 178 7943768 717 control 186 69.8 60.3 196 920 4051 666 control 187 76.7 63.5166 866 4157 720 control 188 72.1 62.0 191 883 4182 704 control 189 54.361.2 222 1079 4240 674 control 190 55.7 61.1 193 942 4125 692 control191 65.0 control 192 61.1 60.4 191 902 4189 710 invention 10 88.1 62.9249 1202 4292 634 Crack Growth Rate Abrasion loss Tan δ Tan δ Sample No.Rebound (cm/million cycles) (g) @ 0° C. @ 60° C. control 177 54.6 0.131control 178 55.6 2.34 0.1649 0.194 0.129 control 179 53.7 2.78 0.16200.200 0.140 control 180 52.9 2.98 0.1385 0.220 0.153 control 181 51.03.41 0.1189 0.267 0.185 control 182 49.9 3.11 0.1076 0.270 0.194 control183 50.1 3.15 0.1086 0.284 0.192 control 184 48.0 3.11 0.1085 0.2840.208 control 185 47.5 4.59 0.0937 0.306 0.209 control 186 48.5 4.060.1008 0.295 0.211 control 187 47.7 3.53 0.1041 0.297 0.198 control 18847.8 3.79 0.0985 0.285 0.207 control 189 47.5 3.71 0.0957 0.306 0.203control 190 46.8 4.14 0.0962 0.300 0.200 control 191 47.4 0.226 control192 46.5 4.78 0.0897 0.301 0.226 invention 10 48.2 0.69 0.0942 0.2710.178

[0208]FIG. 18 shows the dispersion quality and MW_(sol) of the inventionand control samples described above comprising N234 carbon black.Selected invention and control samples shown in FIG. 18 comprised oil,as set forth above. The data shown in FIG. 18 clearly reveals that themacro-dispersion quality of the novel elastomer composites of theinvention comprising N234 carbon black, over a wide range of MW_(sol)values, is significantly superior to that of the control samples. Themacro-dispersion values for the elastomer composites of the inventioncomprising N234 carbon black, as shown in FIG. 18 are described by thefollowing equations:

D(%)<0.3%  (17)

[0209] when MW_(sol)<0.35×10⁶; and

log(D)<log(0.3)+2.8×[MW _(sol)−(0.35×10⁶)]×10⁻⁶  (18)

[0210] when 0.35×10⁶<MW_(sol)<1.1×10⁶.

[0211] None of the control samples achieved macro-dispersion quality of0.3% or better at any MW_(sol), even after dry mixing sufficiently todegrade MW_(sol) below 0.35×10⁶. In contrast, elastomer composites ofthe invention comprising N234 carbon black and having MW_(sol) greaterthan 0.35×10⁶ have excellent macro-dispersion, such as D(%) not morethan 0.3% or even 0.2%. Compound properties and performancecharacteristics for invention sample No. 14 and various control samplesshown in FIG. 18, comprising N234 carbon black, are set forth in Table31 below. It can be seen that invention sample No. 14 has goodresistance to crack growth, as indicated by its crack growth rate valueof only 2.08 cm/million cycles. TABLE 31 Compound Properties of NRCompounds Containing N234 Carbon Black at 55 phr Loading Mooney E100E300 Tensile EB Sample No. ML(1 + 4)@100C Hardness (psi) (psi) (psi) (%)control 273 94.5 68.0 388 2077 3718 511 control 274 121.6 69.6 464 22993925 501 control 275 121.4 72.5 564 2545 3994 472 control 276 132.2 71.9511 2259 3964 520 control 277 79.6 68.5 468 2453 3857 469 control 27896.3 70.0 531 2499 3874 469 control 279 108.6 69.0 406 2131 3863 532control 280 120.3 71.5 476 2273 3852 502 control 281 76.4 69.7 556 27234027 451 control 282 89.8 69.8 553 2574 3896 465 control 283 93.6 69.6506 2416 3867 475 control 284 106.7 71.8 526 2384 3788 484 control 28573.3 69.3 529 2586 3831 444 control 286 79.2 69.5 531 2574 3856 456control 287 77.8 70.7 544 2486 3834 461 control 288 82.8 71.2 485 22953799 499 invention 14 82.6 71.5 500 2440 3883 531 Crack Growth RateAbrasion loss Tan δ Tan δ Sample No. Rebound (cm/million cycles) (g) @0° C. @ 60° C. control 273 45.9 2.14 0.0563 0.285 0.183 control 274 47.21.84 0.0583 0.274 0.173 control 275 46.1 1.70 0.0538 0.284 0.172 control276 46.9 1.21 0.0620 0.270 0.173 control 277 47.1 2.22 0.0628 0.3050.173 control 278 45.8 2.40 0.0634 0.299 0.196 control 279 45.4 2.000.0680 0.306 0.198 control 280 44.2 1.81 0.0648 0.298 0.198 control 28146.3 3.10 0.0598 0.293 0.174 control 282 46.5 2.33 0.0537 0.307 0.182control 283 46.4 2.41 0.0594 0.309 0.186 control 284 44.2 1.99 0.05790.304 0.190 control 285 47.0 2.99 0.0554 0.295 0.178 control 286 45.62.85 0.0551 0.294 0.172 control 287 45.4 2.93 0.0569 0.305 0.187 control288 44.0 2.39 0.0647 0.316 0.198 invention 14 45.1 2.08 0.0698 0.3100.198

[0212]FIG. 19 shows the dispersion quality and MW_(sol) of the inventionand control samples described above comprising N110 carbon black at 55phr loading. The data shown in FIG. 19 clearly reveals that themacro-dispersion quality of the novel elastomer composites of theinvention comprising N110 carbon black, over a wide range of MW_(sol)values, is significantly superior to that of the control samples. Themacro-dispersion values for the elastomer composites of the inventioncomprising N110 carbon black, as shown in FIG. 19, are described by thefollowing equations:

D(%)<0.5%  (19)

[0213] when MW_(sol)<0.35×10⁶; and

[0214] log(D)<log(0.5)+2.5×[MW _(sol)−(0.6×10⁶)]×10⁻⁶  (20)

[0215] when 0.35×10⁶<MW_(sol)<1.1×10⁶.

[0216] None of the control samples achieved macro-dispersion quality of0.5% at any MW_(sol), even after dry mixing sufficiently to degradeMW_(sol) below 0.35×10⁶. In contrast, elastomer composites of theinvention comprising N110 carbon black and having MW_(sol) above0.35×10⁶ have excellent macro-dispersion, such as D(%) less than 0.2%.

[0217]FIG. 20 shows the dispersion quality and MW_(sol) of inventionsample 22 and the control samples described above comprising N351 carbonblack at 33 phr loading. The data shown in FIG. 20 clearly reveals thatthe macro-dispersion quality of the novel elastomer composites of theinvention comprising N351 carbon black, over a wide range of MW_(sol)values, is significantly superior to that of the control samples. Themacro-dispersion values for the elastomer composites of the inventioncomprising N351 carbon black, as shown in FIG. 20, are described by thefollowing equations:

D(%)<0.3%  (21)

[0218] when MW_(sol)<0.55×10⁶; and

log(D)<log(0.3)+2.0×[MW _(sol)−(0.55×10⁶)]×10⁻⁶  (22)

[0219] when 0.55×10⁶<MW_(sol)<1.1×10⁶.

[0220] None of the control samples achieved macro-dispersion quality of1.0% at any MW_(sol), even after dry mixing sufficiently to degradeMW_(sol) below 0.35×10⁶. In contrast, elastomer composites of theinvention comprising N351 carbon black and having MW_(sol) above0.35×10⁶ have excellent macro-dispersion, such as D(%) less than 0.2%.

[0221]FIG. 21 shows the dispersion quality and MW_(sol) of the inventionsample No. 23 and control samples described above comprising STERLING®6740 carbon black at 55 phr loading. The data shown in FIG. 21 clearlyreveals that the macro-dispersion quality of the novel elastomercomposites of the invention comprising STERLING® 6740 carbon black, overa wide range of MW_(sol) values, is significantly superior to that ofthe control samples. The macro-dispersion values for the elastomercomposites of the invention comprising STERLING® 6740 carbon black, asshown in FIG. 21 are described by the following equations:

D(%)<0.1%  (23)

[0222] when MW_(sol)<0.3×10⁶; and

log(D)<log(0.1)+2.0×[MW _(sol)−(0.3×10⁶)]×10⁻⁶  (24)

[0223] when 0.3×10⁶<MW_(sol)<1.1×10⁶.

[0224] None of the control samples achieved macro-dispersion quality of0.1% or even 0.2% at any MW_(sol), even after dry mixing sufficiently todegrade MW_(sol) below 0.3×10⁶.In contrast, elastomer composites of theinvention comprising STERLING®6740 carbon black and having MW_(sol)above 0.3×10⁶ have excellent macro-dispersion, such as D(%) less than0.2% and even less than 0.1%. Compound properties and performancecharacteristics for invention sample No. 23 and the control samplesshown in FIG. 21, comprising STERLING® 6740 carbon black, are set forthin Table 32 below. It can be seen that invention sample No. 23 has goodresistance to crack growth, as indicated by its crack growth rate valueof only 0.91 cm/million cycles. In fact, the invention sample is farsuperior to the corresponding control samples. This is believed to bedue largely to the better MW_(sol) and macro-dispersion of carbon blackin the invention sample, as discussed above. TABLE 32 CompoundProperties of NR Compounds Containing STERLING 6740 Carbon Black at 55phr Loading Mooney E100 E300 Tensile EB Sample No. ML(1 + 4)@100CHardness (psi) (psi) (psi) (%) control 412 75.50 65.1 487.0 2308.0 3519451 control 413 85.70 65.7 489.0 2314.0 3655 479 control 414 92.70 67.7482.0 2243.0 3613 472 control 415 99.60 66.9 492.0 2260.0 3572 477control 416 74.50 65.8 521.0 2468.0 3584 445 control 417 78.20 67.1502.0 2372.0 3445 436 control 418 82.00 66.0 534.0 2418.0 3604 453control 419 86.10 67.8 540.0 2330.0 3620 475 control 420 66.70 66.0515.0 2382.0 3468 444 control 421 76.30 67.8 488.0 2310.0 3375 440control 422 78.30 65.8 548.6 2440.0 3549 442 control 423 82.10 66.5487.0 2219.0 3452 466 control 424 64.80 66.5 541.0 2448.0 3397 425control 425 67.50 66.5 524.0 2374.0 3474 445 control 426 70.30 66.9546.0 2351.0 3428 446 control 427 71.00 68.1 554.0 2340.0 3322 435invention 23 110.50  64.8 453.6 2241.0 3324 443 Crack Growth RateAbrasion loss Tan δ Tan δ Sample No. Rebound (cm/million cycles) (g) @0° C. @ 60° C. control 412 59.8 5.04 0.127 0.202 0.107 control 413 60.03.63 0.128 0.203 0.108 control 414 59.3 3.96 0.126 0.208 0.114 control415 58.8 4.56 0.12  0.217 0.118 control 416 60.3 5.67 0.117 0.188 0.094control 417 60.0 4.67 0.112 0.202 0.104 control 418 59.3 4.23 0.1250.204 0.105 control 419 57.5 3.22 0.122 0.218 0.117 control 420 60.04.23 0.131 0.204 0.099 control 421 58.8 3.84 0.127 0.206 0.105 control422 59.8 3.98 0.126 0.210 0.106 control 423 56.8 3.85 0.12  0.213 0.117control 424 58.3 4.54 0.131 0.200 0.104 control 425 58.8 3.65 0.1290.207 0.100 control 426 58.0 3.07 0.134 0.211 0.110 control 427 56.93.25 0.126 0.217 0.115 invention 23 57.3 0.91 0.1642 0.204 0.124

[0225] Addition Examples: Cured Samples

[0226] A number of the masterbatch samples described above, includingboth selected invention samples and corresponding control samples, werecured and tested. Specifically, samples were mixed accordingly to StageII in Table 8, above, using the formulation of Table 9, to produce afinal compound. The final compound in each case was then cured in a moldusing standard techniques at about 150° C. until substantially completecure was achieved. Performance characteristics of the cured samples weredetermined by measuring their respective crack growth rates inaccordance with the measurement technique set forth above, i.e., using arotating flexing machine per ASTM D3629-94. The rotating type flexingmachine used to measure crack growth is commercially available and wellknown. It is discussed, for example, in the Proceedings of theInternational Rubber Conference, 1995 (Kobe, Japan), Paper No. 27A-6 (p.472-475). The compounds were tested at 100° C. and at a 45° flexingangle. It is generally accepted by those skilled in the art that crackgrowth rate in such compounds is affected by the molecular weight of thenatural rubber and the dispersion quality of the carbon black i.e., bythe MW_(sol) and D(%) values of the compounds. Higher MW_(sol) and lowerD(%) correlate well with reduced crack growth rate. The crack growthrate and other information for invention samples nos. 9, 10 and 16 areset forth in Table 33 below. The corresponding test results forcorresponding control samples is set forth in Table 34 below, grouped bychoice of carbon black. Also, Tan δ_(max)@60° C. was measured forinvention samples nos. 24-32 and for corresponding control samples. TheTan δ_(max)@60° C. values for the invention samples are set forth inTable 35 below. The corresponding test results for control samples isset forth in Table 36 below.

[0227] Control samples No. 444-450 shown in Table 36 were made inaccordance with the procedures described above for control sample codeM2D1 using RSS1 natural rubber. All used carbon black N234 at theloading level (phr) shown in Table 36, along with 5 phr extender oil.TABLE 33 Crack Growth Rate of Invention Samples Invention Sample No.CB/Loading/Oil Mw_(sol)(K) CGR (cm/million cycles)  9 N326/55/0 666 0.7710 R660/55/0 678 0.69 16 N234/55/0 500 0.88

[0228] TABLE 34 Crack Growth Rate of Control Samples N234/55phr/0N326/55phr/0 RSS1 RSS1 Sample Mw_(sol) CGR Sample Mw_(sol) CGR Code No.(K) (cm/million cycles) Code No. (K) (cm/million cycles) M1D1 273 5852.14 M1D1 145 550 2.84 M1D2 274 689 1.84 M1D2 146 636 2.52 M1D3 275 7691.70 M1D3 147 650 2.03 M1D4 276 896 1.21 M1D4 148 724 1.63 M2D1 277 5802.22 M2D1 149 517 3.39 M2D2 278 602 2.40 M2D2 150 572 2.77 M2D3 279 6312.00 M2D3 151 613 2.61 M2D4 280 667 1.81 M2D4 152 696 2.79 M3D1 281 4573.10 M3D1 153 489 3.12 M3D2 282 476 2.33 M3D2 154 521 3.35 M3D3 283 4932.41 M3D3 155 504 3.63 M3D4 384 495 1.99 M3D4 156 538 3.55 M4D1 285 3722.99 M4D1 157 415 3.02 M4D2 286 382 2.85 M4D2 158 447 3.81 M4D3 287 3812.93 M4D3 159 466 3.23 M4D4 288 403 2.39 M4D4 160 469 3.19 Regal660/55phr/0 Regal 660/55phr/0 RSS1 RSS1 Sample Mw_(sol) CGR SampleMw_(sol) CGR Code No. (K) (cm/million cycles) Code No. (K) (cm/millioncycles) M1D1 177 674 M3D1 185 473 4.59 M1D2 178 792 2.34 M3D2 186 5064.06 M1D3 179 891 2.78 M3D3 187 562 3.53 M1D4 180 676 2.98 M3D4 188 5593.79 M2D1 181 598 3.41 M4D1 189 401 3.71 M2D2 182 602 3.11 M4D2 190 4264.14 M2D3 183 697 3.15 M4D3 191 466 M2D4 184 659 3.11 M4D4 192 449 4.78

[0229] TABLE 35 Tan δ at 60° C. for Invention Samples Invention SampleNo. N234 Loading/Oil (phr) Mw_(sol)(K) Max.Tan δ @ 60° C. 24 48/5 5690.169 25 53/5 485 0.176 26 58/5 447 0.191 27 63/5 403 0.219 28 68/5 3780.227 29 49/5 618 0.159 30 54/5 482 0.171 31 63/5 390 0.228 32 65/5 3250.224

[0230] TABLE 36 Tan δ at 60° C. for Control Samples MW D N234Loading/Oil Max.Tan D Sample No. (K) (%) (phr) (@60 C) 444 428 0.25 37150.154 445 409 0.37 4215 0.170 446 379 0.42 4615 0.179 447 361 0.58 51150.195 448 366 0.27 5315 0.212 449 290 0.39 5815 0.215 450 296 0.64 63150.245

[0231] It can be seen from a comparison of Table 33 and 34 thatadvantageously lower crack growth rate is achieved by the inventionsamples, compared to the control samples. Lower crack growth ratecorrelates with good durability and related characteristics for numerousapplications, including tire applications and the like. In addition, itcan be seen from a comparison of Tables 35 and 36 that better Tanδ_(max) values are achieved by the invention samples, that is, valueswhich are lower than the values of the control sample. Accordingly,improved performance is achieved by the invention samples for numerousproduct applications including, for example, tire applications and thelike requiring low hysteresis for correspondingly low rollingresistance.

[0232] The advantageous performance characteristics of the elastomercomposites of the invention are exemplified by the crack growth rate ofinvention sample no.16 comprising N234 carbon black and correspondingtest results for control samples nos. 273 to 288 shown graphically inFIG. 22. Specifically, FIG. 22 clearly demonstrates a correlationbetween MW_(sol) and crack growth rate for the control samples, as wellas the advantageous impact of excellent macro-dispersion in theelastomer composites of the present invention. It should be understoodthat the MW_(sol) values shown in FIGS. 22-24 and in Tables 33-36 arefor the masterbatch materials prior to cure. The molecular weight of thecured material is understood to correlate well to the MW_(sol) value ofthe uncured masterbatch. The crack growth rate of the control samplesover an MW_(sol) range of about 0.25×10⁶ to 0.6×10⁶ is seen to fit wellalong a straight line correlation to MW_(sol). In contrast, theinvention sample no. 16 at MW_(sol) 0.5×10⁶ has significantly better(i.e., lower) crack growth rate than any of the corresponding controlsamples, due to the better macro-dispersion D(%) of the inventionsample. This is further established by the similar showing in FIG. 23,wherein the crack growth rate of invention sample no. 9 comprising N326carbon black is seen to be significantly lower than that of any of thecorresponding control samples nos. 145 to 160, and is well below thecorrelation line. Likewise in FIG. 24 the excellent macro-dispersion ofinvention sample no. 10 is seen to result again in a crack growth valuewhich lies far below the correlation line between crack growth rate andMW_(sol) established by the corresponding control samples nos. 177 to192. In FIG. 25, the max tan δ at 60° C. is shown graphically to bebetter, i.e., lower, for invention samples nos. 24 to 28 and inventionsamples nos. 29 to 32 than for corresponding control samples nos. 444 to450.

[0233] The superior crack growth results discussed above for elastomercomposites of the present invention not only demonstrates advantageousfatigue properties, but also indicates advantageous fracture properties,such as excellent tear and cut-and-chip resistance. The superiorhysteresis results discussed above for the elastomer composites of thisinvention not only demonstrate advantageously low rolling resistance(and correspondingly higher fuel economy) for motor vehicle tireapplications, but also indicates advantageous improvement in relatedperformance properties, such as reduced heat build-up. One or more ofthese superior properties, fatigue and fracture resistance, lowhysteresis, low heat build-up, etc., render elastomer composites of thepresent invention well suited for use in commercial applications such astire applications and in industrial rubber products. Regarding tireapplications, various preferred embodiments of the invention areparticularly well-suited for use as: tire tread, especially in tread forradial and bias truck tires, off-the-road (“OTR”) tires, airplane tiresand the like; sub-tread; wire skim; sidewalls; cushion gum for retreadtires; and similar tire applications. The superior performancecharacteristics achieve by various preferred embodiments of theinvention can provide improved tire durability, tread life and casinglife, better fuel economy for the motor vehicle and other advantages.Regarding industrial rubber products, various preferred embodiments ofthe invention are particularly well-suited for use as: engine mounts,hydro-mounts, bridge bearings and seismic isolators, tank tracks ortread, mining belts and similar products applications. The superiorperformance characteristics achieved by various preferred embodiments ofthe invention can provide improved fatigue life, durability and otheradvantages for such product applications.

[0234] FIGS. 26-29 are graphical representations of carbon blackmorphology, structure (DBPA) and surface area (CTAB), correspondinggenerally to FIG. 8. Carbon black morphology region 261 in FIG. 26includes carbon blacks currently in commercial use for OTR tire treadapplications. Arrow 262 indicates the direction in which region 261 canbe advantageously extended in accordance with the present invention.Performance characteristics such as cut-and-chip resistance, crackgrowth resistance and tear resistance are understood to improvegenerally in the direction of trend arrow 262 subject, however, in thepast, to offsetting degradation of these and other characteristics dueto reduced molecular weight of the natural rubber and/or poorermacro-dispersion resulting from the use of such higher surface area,lower structure carbon blacks. Elastomer composites of the presentinvention can employ such lower structure, higher surface area carbonblack indicated by trend arrow 262 to achieve significantly improved OTRtrend materials, in view of their excellent macro-dispersion andMW_(sol).

[0235] Similarly, carbon black morphology region 271 in FIG. 27 includescarbon blacks currently in commercial use for truck and bus (T/B) tiretread applications. Arrow 272 indicates the direction in which region271 can be advantageously extended in accordance with the presentinvention. Performance characteristics, such as wear resistance, areunderstood to improve generally in the direction of trend arrow 272subject, however, in the past, to offsetting degradation of these andother characteristics due to reduced molecular weight of the rubberand/or poorer macro-dispersion resulting from use of such higher surfacearea carbon blacks. Elastomer composites of the present invention canemploy such higher surface area carbon blacks indicated by trend arrow272 to achieve improved T/B tread materials, in view of their excellentmacro-dispersion and MW_(sol).

[0236] Similarly, carbon black morphology regions 281 and 283 in FIG. 28show carbon blacks currently in commercial use for tread base andpassenger car (PC) tire tread, respectively. Trend arrows 282 and 284indicate the direction in which region 281 and 283, respectively, can beadvantageously extended in accordance with the present invention.Performance characteristics such as heat build-up (HBU) and rollingresistance are understood to improve for tread base in the direction oftrend arrow 282 subject, however, in the past, to offsetting degradationof these and other characteristics due to reduced molecular weight ofthe rubber and/or poorer macro-dispersion resulting from use of suchhigher surface area, lower structure carbon blacks. Likewise,performance characteristics such as rolling resistance are understood toimprove for PC tread in the direction of trend arrow 284 subject,however, in the past, to offsetting degradation of these and othercharacteristics due to reduced molecular weight of the rubber and/orpoorer macro-dispersion resulting from use of such higher surface area,lower structure carbon blacks. Elastomer composites of the presentinvention can employ higher surface area, lower structure carbon blacksindicated by arrows 282 and 284 to achieve improved tread base and PCtread, respectively, in view of the excellent macro-dispersion and theoptional preservation of high molecular weight in such elastomercomposites.

[0237] Similarly, carbon black morphology regions 291, 293 and 294 inFIG. 29 show carbon blacks currently in commercial use for sidewall,apex and steel belt tire applications, respectively. Trend arrows 292and 295 indicate the direction in which region 291 and 294,respectively, can be advantageously extended in accordance with thepresent invention. Performance characteristics such as heat build-up(HBU) and fatigue life are understood to improve for sidewall in thedirection of trend arrow 292 subject, however, in the past, theoffsetting degradation of these and other characteristics due to reducedmolecular weight of the rubber and/or poorer macro-dispersion resultingfrom use of such lower structure carbon blacks. Likewise, performancecharacteristics such as heat buildup, processing and wire adhesion areunderstood to improve for steel belt elastomeric materials in thedirection of trend arrow 295 subject, however, in the past, tooffsetting degradation of these and other characteristics due to reducedmolecular weight of the rubber and/or poorer macro-dispersion resultingfrom use of such higher surface area, lower structure carbon blacks.Elastomer composites of the present invention can employ higher surfacearea and/or lower structure carbon blacks as indicated by arrows 292 and295 to achieve improved sidewall and steel belt rubber materials,respectively, in view of the excellent macro-dispersion and the optionalpreservation of high molecular weight in such elastomer composites.

[0238] Additional Examples: Preferred Embodiment and Control SamplesComprising Other Fillers

[0239] Additional samples of elastomer composites in accordance withcertain preferred embodiments of the present invention, andcorresponding control samples, were prepared. A first group of theseemployed a multiphase aggregate filler of the type referred to above asa silicon-treated carbon black.

[0240] Specifically, invention samples nos. 33-34 employed ECOBLACK®silicon-treated carbon black commercially available from CabotCorporation (Billerica, Mass.). Such ECOBLACK® filler has morphologicalproperties, i.e., structure and surface area, similar to that of carbonblack N234. Sample no. 33 employed 45 phr ECOBLACK® filler and noextender oil. Sample no. 34 employed 68 phr ECOBLACK® filler and noextender oil. Typical filler and extender oil usage for various productapplications are shown in Table 37, for elastomer composites of theinvention comprising natural rubber and a blend of carbon black andsilica filler. It should be understood that the use of silica filler inthe compositions shown in Table 37 would typically replace a like amountof the carbon black filler. TABLE 37 Typical NR Formulations for TireApplications Application Carbon Black Type Carbon Black Loading OilLoading Silica Loading Truck/Bus Tread N110,N115,N121,N134,N220,N29940-60 phr 0-20 phr 0-10 phr OTR Tread N110,N115,N220,N231 45-55 phr 5-10phr 5-20 phr Steel Belt N326 50-76 phr 0-5 phr  0-10 phr Truck/Bus TreadBase N330,N550 40-60 phr 0-20 phr Carcass Ply N326,N330,N550 40-60 phr5-30 phr Sidewall N330,N351,N550 30-60 phr 5-30 phr Apex N326,N330,N35150-90 phr 0-20 phr LRR PC Tread N234,N299,N339,N343,N347,N351 40-60 phr0-30 phr

[0241] A second group of samples employed a blend or mixture of silicaand carbon black. In embodiments of the present invention employing ablend of carbon black and silica fillers, it is generally preferred thatthey be used in weight ratio of at least about 60:40. That is, thecarbon black preferably comprises at least about 60 weight percent ofthe filler to achieve good coagulation of the elastomer and to reduce oreliminate reagglomeration of the silica in the masterbatch. Inparticular, in examples nos. 35-38, as shown in Table 40, carbon blackis used together with particulate SiO₂ filler HiSil® 233 available fromPPG Industries (Pittsburgh, Pa., USA), having surface area BET of 150m²/g, surface area DBPA of 190 mils/100 g, pH of 7 and a primaryparticulate size of 19 nanometers.

[0242] All of the invention samples, i.e., additional invention samplesnos. 33-38, were prepared in accordance with the procedures andapparatus used for invention samples 1-32, as described above. Processand apparatus details for each of invention samples nos. 33-38 is givenin Table 38, below. The field latex or concentrate employed in samplesnos. 33-38, as the case may be, is the same as described above withreference to Table 24. It will be appreciated that the data in Table 38parallels that provided in Table 25, above, for invention samples nos.1-32. The carbon black filler “CRX2000” listed in Table 38 is theECOBLACK® silicon-treated carbon black described above. TABLE 38Invention Sample Production Details Cabot Elastomer Composite SlurryNozzle Tip CB Slurry Invention Carbon Black HiSil 233 Oil loading Dia.Land length CS conc. Sample No. Latex type Type Loading (phr) Loading(phr) (phr) (in) (in) (% wt) 33 field latex CRX2000 46  0 0 0.020 0.514.5 34 field latex CRX2000 58  0 0 0.020 0.5 14.5 35 field latex N22043 10 5 0.025 0.5 13.9 36 field latex N234 41  9 0 0.020 0.5 13.5 37field latex N234 31 20 0 0.020 0.5 14.0 38 latex concentrate STERLING6740 29 20 0 0.020 0.5 15.5 Coagulum Zone Invention 1st portion 2ndportion 3rd portion 4th portion Sample No. Dia. (in) Length (in) Dia.(in) Length (in) Dia. (in) Length (in) Dia. (in) Length (in) 33 0.19 3.00.27 1.6 0.38 2.3 0.53 3.2 34 0.19 3.0 0.27 1.6 0.38 2.3 0.53 3.2 350.19 3.0 0.27 1.6 0.38 2.3 0.53 3.2 36 0.19 3.0 0.27 1.6 0.38 2.3 0.533.2 37 0.19 3.0 0.27 1.6 0.38 2.3 0.53 3.2 38 0.19 3.0 0.27 1.6 0.38 2.30.53 3.2 Mixing Zone MicroFluidizer Invention Slurry flow rate Slurryvelocity Antioxidant Latex flow rate Latex velocity Inlet pressureOutlet pressure Sample No. (lb/min) (ft/sec) TNPP (phr) Santoflex (phr)(lbs/min) (ft/sec) (psi) (psi) 33 6.2 710 0.3 0.4 Field 7.4 10.7 1700034 6.2 710 0.3 0.4 Field 5.8 8.3 17000 35 5.2 380 0.3 0.4 Field 4.9 7.114500 36 5.0 576 0.3 0.4 Field 4.3 6.2 10000 37 4.8 550 0.3 0.4 Field4.1 5.9  9500 38 5.1 580 0.3 0.4 Conc 2.2 3.2  9000 Slurry NozzleDewatering Drying and Cooling Production Invention Tip Pressure Initialcrumb Final crumb Product Product Mixer Rate Invention Sample No. (psi)moisture (%) moisture (%) temp. (° F.) moisture (%) Type (lb/hr) SampleNo. 33 — 77.5 >8.0 435 0.2 T-block 66 33 34 — 78.0 1.6 470 0.3 T-block52 34 35 1650 77.9 >4.0 360 0.4 T-block 54 35 36 3000 79.2 1.0 475 0.5T-block 39 36 37 2930 78.9 12.3 435 0.4 T-block 34 37 38 2600 69.7 4.2455 0.2 T-block 48 38

[0243] The control samples 451-498 were prepared in accordance with theprocedures and apparatus described above for control samples nos. 1-450.The processing code (see Table 13 above), filler loading, rubber,MW_(sol) and macro-dispersion for masterbatches 451-466 are set forthbelow in Table 39. The processing code, filler loading, rubber, MW_(sol)and macro-dispersion values of the invention samples nos. 33-38 (alongwith the filler and oil loadings for convenient reference) are shown inTable 40. It will be seen from Table 39 that control samples 451-466correspond in composition to invention samples nos. 33 and 34.Similarly, control samples nos. 467-498 correspond to invention samplesnos. 35-38. TABLE 39 CRX 2000/44/0 CRX 2000/58/0 RSS1 RSS1 SampleMw_(sol) Sample Mw_(sol) Code No. (K) D (%) No. (K) D (%) M2 909 909 M3590 590 M2D1 451 481 3.48 459 333 8.61 M2D2 452 474 3.68 460 392 5.71M2D3 453 489 7.17 461 388 9.48 M2D4 454 515 6.28 462 394 8.05 M3D1 455393 2.89 463 280 2.23 M3D2 456 422 2.87 464 298 2.13 M3D3 457 435 4.15465 350 4.05 M3D4 458 449 3.23 466 379 7.22

[0244] TABLE 40 Sol Molecular Weight and Undispersed Area of InventionSamples Invention Sample No. CB/Loading/Oil Mw_(sol) (K) D (%) 33 CRX2000/44/0 380 0.18 34 CRX 2000/58/0 448 0.10 35 N220/Hilsil 233/43/10/5500 0.14 36 N234/Hilsil 233/40/10/0 490 0.36 37 N234/Hilsil 233/30/20/0399 0.23 38 STERLING 6740/Hilsil 233/30/20/0 354 0.39

[0245] TABLE 41 N220/Hilsil 233/43/10/5 N234/Hilsil 233/40/10/0 RSS1RSS1 Sample Mw_(sol) Sample Mw_(sol) Code No. (K) D (%) No. (K) D (%) M2803 909 M3 601 590 M2D1 467 493 1.51 475 443 8.74 M2D2 468 537 2.61 476517 10.9 M2D3 469 523 2.82 477 569 12.5 M2D4 470 615 2.95 478 592 8.25M3D1 471 417 0.95 479 358 6.65 M3D2 472 438 1.40 480 420 13.8 M3D3 473433 2.15 481 516 13.9 M3D4 474 485 2.22 482 447 7.25 STERLINGN234/Hilsil 233/30/20/0 6740/Hilsil 233/30/20/0 RSS1 RSS1 SampleMw_(sol) Sample Mw_(sol) Code No. (K) D (%) No. (K) D (%) M2 909 909 M3590 590 M2D1 483 394 4.37 491 430 3.77 M2D2 484 507 5.66 492 488 4.39M2D3 485 526 4.7 493 517 5.37 M2D4 486 568 5.94 494 563 4.66 M3D1 487377 8.39 495 375 3.5 M3D2 488 363 4.49 496 380 2.73 M3D3 489 376 5.07497 419 2.72 M3D4 490 432 5.26 498 448 3.29

[0246] The excellent carbon black dispersion in the masterbatches ofinvention samples 33-38 is demonstrated by comparison of themacro-dispersion quality and MW_(sol) values shown in Tables 39-41. Theinvention samples nos. 33-34 made with ECOBLACK® silicon-treated carbonblack, and the corresponding control samples are compared in thesemi-log plot of FIG. 30. Excellent carbon black dispersion is seen inFIG. 30 for the invention samples, representing preferred embodiments ofelastomer composites in accordance with the present disclosure. Theinvention samples advantageously are below line 301 in FIG. 30, whereasall of the control samples have poorer dispersion, being above line 301.In fact, the preferred embodiments shown in FIG. 30 fall below a D(%)value of 0.2% even at an MW_(sol) value advantageously exceeding0.4×10⁶. The data shown in FIG. 30 clearly reveals that themacro-dispersion quality of the novel elastomer composites, disclosedhere, comprising silicon-treated carbon black is significantly superiorto that achievable using comparable ingredients in prior dry mixingmethods. The macro-dispersion values for the elastomer composites of theinvention shown in FIG. 30 are described by the following equations:

D(%)<1.0%  (25)

[0247] when MW_(sol) is less than 0.4×10⁶; and

log(D)<log(1.0)+2.0×[MW _(sol)−(0.4×10⁶)]×10⁻⁶  (26)

[0248] when 0.4×10⁶<MW_(sol)<1.1×10⁶

[0249] It will be recognized that D(%) is the percent undispersed areameasured for defects greater than 10 microns and 1% is the thresholdmacro-dispersion quality for the masterbatches in accordance with thesepreferred embodiments of the present invention. That is, none of the drymasticated masterbatches achieved macro-dispersion quality of 1.0% orbetter at any MW_(sol), even after dry mixing sufficiently to degradeMW_(sol) below 0.4×10⁶. The preferred embodiments shown in FIG. 30 fallwell below the threshold. It can be seen that the elastomer compositesof the invention comprising silicon-treated carbon black provideheretofore unachieved balance between macro-dispersion quality andMW_(sol).

[0250] Invention samples nos. 35-38 comprising carbon black blended withsilica filler and corresponding control samples are compared in thesemi-log plot of FIG. 31. Specifically, FIG. 31 shows themacro-dispersion values and MW_(sol) values of the invention samplesnos. 35-38 and corresponding control samples nos. 467-498. Excellentcarbon black dispersion is seen in FIG. 31 for the invention samples,representing preferred embodiment of elastomer composites in accordancewith the present disclosure. The invention samples advantageously arebelow line 311 in FIG. 31, whereas all of the control samples havepoorer dispersion, being above line 311. In fact, all of the preferredembodiments shown in FIG. 31 fall below a D(%) value of 0.4%. The datashown in FIG. 31 clearly reveals that the macro-dispersion quality ofthe novel elastomer composites, disclosed here, comprising carbonblack/silica blends over a range of MW_(sol) values, is significantlysuperior to that achievable using comparable ingredients in prior drymastication mixing methods. The macro-dispersion values for theelastomer composites of the invention shown in FIG. 31 are described bythe following equations:

D(%)<0.8%  (27)

[0251] when MW_(sol) is less than 0.5×10⁶; and

log(D)<log(0.8)+2.2×[MW _(sol)−(0.5×10⁶)]×10⁻⁶  (28)

[0252] when 0.5×10⁶<MW_(sol)<1.1×10⁶

[0253] It will be recognized that D(%) is the percent undispersed areameasured for defects greater than 10 microns and 0.8% is the thresholdmacro-dispersion quality for masterbatches in accordance with thesepreferred embodiments of the present invention. That is, none of the drymasticated masterbatches achieved macro-dispersion quality of 0.8% orbetter at any MW_(sol) even after dry mixing sufficiently to degradeMW_(sol) below 0.4×10⁶. The preferred embodiments shown in FIG. 31 fallwell below the threshold macro-dispersion value of 0.8%, and even below0.4%. It can be seen that the elastomer composites of the inventioncomprising carbon black/silica blend filler provide heretoforeunachieved balance between macro-dispersion quality and Mw_(sol).

ADDITIONAL EXAMPLES

[0254] Elastomer composite blends were prepared in accordance with thepresent invention and compared to corresponding blends made using priorknown dry/dry mixing techniques, as now described. The elastomercomposite blends were prepared with elastomer composite samples referredto below as “CEC” or “CEC masterbatch.”

[0255] CEC masterbatches were made using field latex natural rubber andVulcan 7H carbon black (ASTM N234 carbon black) as follows:

[0256] Preparing Elastomer Composite (wet mixing step) Elastomermasterbatch was produced in accordance with the present invention.Specifically, an elastomer masterbatch was produced comprising standardnatural rubber field latex from Malaysia with 71 phr filler consistingof carbon black of commercial grade N234 available from CabotCorporation. The compound formulation (excluding minor ordinary latexadditives) is set forth in Table 7 below. TABLE 7A MasterbatchFormulation Ingredient Parts by Wt. Rubber 100 Carbon Black 71.Santoflex 134 (antioxidant) 0.4 TNPP (antioxidant) 0.3 Total 171.7

[0257] The elastomer masterbatch production apparatus was substantiallyidentical to the apparatus described above with reference to FIGS. 1, 3and 7 of the drawings. The slurry nozzle tip (see reference No. 167 inFIG. 7) was 0.018 inch diameter with a land (see reference No. 168 inFIG. 7) having an axial length of 0.2 inch. The coagulum zone (see No.53 in FIG. 3) included a first portion of 0.188 inch diameter andapproximately 0.985 inch axial length (being partly within the mix-headand party within the extender sealed thereto); a second portion of 0.266inch diameter and 1.6 inch axial length; a third portion of 0.376 inchdiameter and 2.256 axial length; and a fourth portion of 0.532 inchdiameter and 3.190 inch axial length. In addition, there are axiallyshort, faired interconnections between the aforesaid portions.Preparation of the masterbatch is described in further detailimmediately below.

[0258] 1. Carbon Black Slurry Preparation. Bags of carbon black weremixed with deionized water in a carbon black slurry tank equipped withan agitator. The agitator broke the pellets into fragments and a crudeslurry was formed with 15.1 wt. % carbon black. The crude slurry wasrecirculated using a pipeline grinder. During operation, this slurry wascontinually pumped by an air diaphragm pump to a colloid mill forinitial dispersion. The slurry was then fed by a progressing cavity pumpto a homogenizer, specifically, Microfluidizer Model M210 fromMicrofluidics International Corporation for pressurizing and shear, toproduce a finely ground slurry. The slurry flow rate from themicrofluidizer to the mixing zone was set by the microfluidizer speed,the microfluidizer acting as a high-pressure positive displacement pump.Slurry flow rate was monitored with a Micromotion® mass flow meter. Thecarbon black slurry was fed to the microfluidizer at a pressure of about250 psig and the output pressure was set at 7500 psig to an accumulatorset at about 1200 psig output pressure, such that the slurry wasintroduced as a jet into the mixing zone at a flow rate of about 3.6lb/min and at a velocity of about 500 ft/sec.

[0259] 2. Latex Delivery. The latex was charged to a tank, specifically,a 55 gallon feed drum. Antioxidant emulsion was added to the latex priorto charging. Antioxidants were added consisting of 0.3 phr tris nonylphenyl phosphite (TNPP) and 0.4 phr Santoplex® 134 (alkyl-arylp-phenylene diamine mixture). Each of the antioxidants was prepared as a40 wt. % emulsion using 4 parts potassium oleate per 100 partsantioxidant along with potassium hydroxide to adjust the emulsion to apH of approximately 10. A peristaltic pump was used to move the latexfrom the feed tank to the mixing zone of the coagulum reactor. The latexflow rate was 3.2 to 3.3 lbs/min and about 4.8 feet per second, and wasmetered with a Endress+Hauser (Greenwood, Ind., USA) mass flow meter.The desired carbon black loading of a 71 phr was obtained by maintainingproper ratio of the latex feed rate to the carbon black slurry feedrate.

[0260] 3. Carbon Black and Latex Mixing. The carbon black slurry andlatex were mixed by entraining the latex into the carbon black slurry.During entrainment, the carbon black was intimately mixed into the latexand the mixture coagulated. Soft, wet spongy “worms” of coagulum exitedthe coagulum reactor.

[0261] 4. Dewatering. The wet crumb discharged from the coagulum reactorwas about 80% water. The wet crumb was dewatered to about 11 to 13%moisture with a dewatering extruder (The French Oil Mill MachineryCompany; 3½ in. diameter). In the extruder, the wet crumb was compressedand water squeezed from the crumb and through a slotted barrel of theextruder.

[0262] 5. Drying & Cooling. The dewatered crumb dropped into a secondextruder where it was again compressed and heated. Water was flashed offupon expulsion of the crumb through the dieplate of the extruder.Product exit temperature was approximately 280° F. to 310° F. andmoisture content was about 3.0 to 4.0 wt. %. The hot, dry crumb wasrapidly cooled (approximately 20 seconds) to about 100° F. by a forcedair vibrating conveyor. Partially wet crumb was completely dried to lessthan 0.5 wt. % in a forced air convector oven (Aeroglide, Raleigh, N.C.)at a temperature of 200° F.-240° F.

[0263] Dry Mixing Step In the following examples both of the two “drymixing” steps of the dry/dry method used below for comparison andcontrol purposes, and the “dry mixing” step of the wet/dry method of thepresent invention were carried out in a Farrell BR Banbury mixer.

[0264] Reference in the following procedures and the following examplesto “natural rubber masterbatch” refers to the product of the first drymixing stage. The term masticated natural rubber refers to the productof the “natural rubber mastication condition” set forth below. The termNR refers to natural rubber. The term CB refers to carbon black. In allcases, carbon black is N234 carbon black. The full formulations for thewet and dry mixing steps is provided in the formulation tableimmediately below.

[0265] It can be seen from the foregoing examples that excellentproperties are achieved in the elastomer composite blends of the presentinvention. Formulation Ingredients phr Rubber (masticated RSS1 + Taktene220 100.0 or, CEC NR + Taktane 220 or, CEO NR + masticated RSS1 or,masticated RSS1) Carbon Black (V7H) 50.0 Oil (Sundex 790) 5.0Antioxidant 1 (Gontoflax 134) 0.4 Antioxidant 2 (TNPP) 0.3 Zinc Oxide(Azo 66) 4.0 Stearic Acid (Hystrene 5016) 2.0 Accelerator (Santocure NS)1.8 Sulfur 1.0 Total 164.5

Mixing Procedures of CEC NR/BR Blends and Dry NR/BR Blends

[0266] Mixing Method

[0267] 1. Blend natural rubber masterbatch, in which all carbon blackwas loaded, with butadiene rubber and oil. The ratios of natural rubberto butadiene rubber were 90/10, 80/20 and 70/30;

[0268] 2. Blend natural rubber masterbatch, in which all carbon blackand oil were loaded, with butadiene rubber. The ratios of natural rubberto butadiene rubber were 80/20 and 70/30;

[0269] 3. Blend natural rubber masterbatch, in which 50 phr of carbonblack was loaded, with butadiene masterbatch, in which 50 phr of carbonblack was loaded, and oil. The ratios of natural rubber to butadienerubber were 80/20, 70/30, 60/40 and 50/50;

[0270] 4. Blend natural rubber masterbatch, in which 50 phr of carbonblack and all oil were loaded, with butadiene masterbatch, in which 50phr of carbon black was loaded. The ratios of natural rubber tobutadiene rubber were 80/20, 70/30, 60/40 and 50/50;

[0271] 5. Blend CEC masterbatch, in which all carbon black was loaded,with butadiene rubber and oil. The ratios of natural rubber to butadienerubber were 90/10, 80/20 and 70/30;

[0272] 6. Blend CEC masterbatch, in which all carbon black and oil wereloaded, with butadiene rubber. The ratios of natural rubber to butadienerubber were 80/20 and 70/30;

[0273] 7. Blend CEC masterbatch, in which 50 phr of carbon black wasloaded, with butadiene masterbatch, in which 50 phr of carbon black wasloaded, and oil. The ratios of natural rubber to butadiene rubber were80/20, 70/30, 60/40 and 50/50;

[0274] 8. Blend CEC masterbatch, in which 50 phr of carbon black and alloil were loaded, with butadiene masterbatch, in which 50 phr of carbonblack was loaded. The ratios of natural rubber to butadiene rubber were80/20, 70/30, 60/40 and 50/50.

[0275] Mixing Procedures

[0276] A three stage Banbury mix was used for dry mix blends and twostage Banbury mix for CEC blends. Natural rubber was masticated beforefirst stage mix for dry mix blends. Butadiene rubber was used withoutmastication. Natural rubber mastication condition: Fill factor: 0.75Rotor speed: 100 rpm Banbury Temperature: 30° C. Total hatch energy: 950Watt-Hours Banbury mixing procedures: Mixing method 1: Stage 1: Fillfactor; varied Rotor speed: 70 rpm Banbury temperature: 30° C. TimeOperation 0″ add masticated NR 30″ add 40 phr of CB 1′00″ add ½remaining CB 1′30″ add remaining CB 8′ to 13′ dump according to powercurve Fill Dump Sample No. factor Mixing time temp. (° C.) Energy input(KWH) 1-1 (stage 1) 0.87 8′ 140.8 1.45 1-2 (stage 1) 0.65 8′ 148.5 1.591-3 (stage 1) 0.63 10′  167.3 1.89 Stage 2: Fill factor: 0.70 Rotorspeed: 70 rpm Banbury temperature: 30° C. Time Operation 0″ add NRmasterbatch, BR bale, chemicals and oil 3′00″ dump Sample No. DumpTemperature (° C.) Energy input (KWH) 1-1 (stage 2) 113.5 0.42 1-2(stage 2) 116.2 0.48 1-3 (stage 2) 116.4 0.44 Stage 3: Fill factor: 0.65Rotor speed: 70 rpm Banbury temperature: 30° C. Time Operation 0″ addstage 2 compound and curatives 3′00″ dump Sample No Dump Temperature (°C.) Energy input (KWH) 1-1 88.5 0.42 1-2 99.8 0.43 1-3 103.9 0.45 Mixingmethod 2: Stage 1: Fill factor: 0.65 Rotor speed: 70 rpm (50 rpm whentemp. reached 160° C.) Banbury temperature: 30° C. Time Operation 0″ addmasticated NR 30″ add 40 phr of CB 1′00″ add ½ remaining CB 1′30″ addremaining CB 2′00′ add oil 9′ to 13′ dump according to power curveSample No Mixing time Dump temp. (° C.) Energy input (KWH) 2-1 (stage 1)9′ 148 1.60 2-2 (stage 1) 9.5′ 145 1.84 Stage 2: Fill factor: 0.70 Rotorspeed: 70 rpm Banbury temperature: 30° C. Time Operation 0′ add NRmasterbatch, BR bale, chemicals 3′00″ dump Sample No Dump Temperature (°C.) Energy Input (KWH) 2-1 (stage 2) 127 0.48 2-2 (stage 2) 126 0.51Stage 3: Fill factor: 0.65 Rotor speed: 70 rpm Banbury temperature: 30°C. Time Operation 0″ add stage 2 compound and 3′00″ curatives dumpSample ID Dump Temperature (° C.) Energy Input (KWH) 2-1 99 0.42 2-2 1070.44 Mixing method 3: Stage 1: *NR masterbatch: Fill factor: 0.65 RotorSpeed: 70 rpm Banbury temperature: 30° C. Time Operation 0″ addmasticated NR 30″ add 40 phr of CB 1′00″ add remaining CB 9′00″ dumpSample No Dump Temperature (° C.) Energy Input (KWH) 3-1 to 3-4(stage 1) 142 1.51 3-1 to 3-4 (stage 1) 143 1.48 3-1 to 3-4 (stage 1)148 1.52 *BR masterbatch: Fill factor: 0.75 Rotor speed: 85 rpm (60 rpmwhen temp. reached 160° C.) Banbury temperature: 30° C. Time Operation0′ add BR bale 30″ add 30 pbr carbon black 1′00″ add ½ of rest of carbonblack 1′30″ add remaining carbon black 7′00″ dump Sample No DumpTemperature (° C.) Energy Input (KWH) 3-1 to 3-4 (stage 1) 159 1.38 3-1to 3-4 (stage 1) 158 1.35 3-1 to 3-4 (stage 1) 157 1.33 Stage 2: Fillfactor: 0.70 Rotor speed: 70 rpm Banbury temperature: 30° C. TimeOperation 0″ add stage 1 masterbatches and chemicals and oil 3′00″ dumpSample No. Dump Temperature (° C.) Energy Input (KWH) 3-1 (stage 2) 1150.36 3-2 (stage 2) 123 0.40 3-3 (stage 2) 120 0.40 3-4 (stage 2) 1180.37 Stage 3: Fill factor: 0.65 Rotor speed: 70 rpm Banbury temperature:30° C. Time Operation 0″ add stage 2 compound and curatives 3′00″ dumpSample ID Dump Temperature (° C.) Energy input (KWH) 3-1 103 0.44 3-2107 0.45 3-3 109 0.47 3-4  97 0.38 Mixing method 4: Stage 1: *NRmasterbatches Fill factor: 0.65 Rotor speed: 70 rpm Banbury temperature:3° C. Time Operation 0″ add masticated NR 30″ add 40 phr of CB 1′00″ addremaining CB 2′00″ add oil 9′00″ dump Sample No Dump Temperature (° C.)Energy Input (KWH) 4-1 to 4-4 (stage 1) 140 1.49 4-1 to 4-4 (stage 1)136 1.49 4-1 to 4-4 (stage 1) 137 1.40 *BR masterbatch Fill factor: 0.75Rotor speed: 85 rpm (60 rpm when temp. reached 160° C.) Banburytemperature: 30° C. Time Operation 0′ add BR bale 30″ add 30 phr carbonblack 1′00″ add ½ of rest of carbon black 1′30″ add remaining carbonblack 7′00″ dump Sample No. Dump Temperature (° C.) Energy Input (KWH)4-1 to 4-4 (stage 1) 159 1.38 4-1 to 4-4 (stage 1) 158 1.35 4-1 to 4-4(stage 1) 157 1.33 Stage 2: Fill factor: 0.70 Rotor speed: 70 rpmBanbury temperature: 30° C. Time Operation 0″ add stage 1 masterbatchesand chemicals 3′00″ dump Sample No Dump Temperature (° C.) Energy Input(KWH) 4-1 (stage 2) 133 0.52 4-2 (stage 2) 133 0.56 4-3 (stage 2) 1330.55 4-4 (stage 2) 132 0.53 Stage 3: Fill factor: 0.65 Rotor speed: 70rpm Banbury temperature: 30° C. Time Operation 0″ add stage 2 compoundand curatives 3′00″ dump Sample No Dump Temperature (° C.) Energy Input(KWH) 4-1 107 0.48 4-2 108 0.48 4-3 109 0.47 4-4 111 0.48 Mixing method5: Stage 1: Fill factor: 0.75 Rotor speed: 70 rpm Banbury temperature:30° C. Time Operation 0″ add CEC masterbatch 4′ add BR bale 7′ addpowders and oil 9′ dump Sample No Dump Temperature (° C.) Energy Input(KWH) 5-1 (stage 1) 104.2 1.78 5-2 (stage 1) 107.1 1.72 5-3 (stage 1)103.9 1.79 Stage 2: Fill factor: 0.65 Rotor speed: 70 rpm Banburytemperature: 30° C. Time Operation 0″ add stage 1 compound and curatives3′00″ dump Sample No Dump Temperature (° C.) Energy Input (KWH) 5-1 76.70.46 5-2 81.0 0.48 5-3 83.3 0.45 Mixing method 6: Stage 1: Fill factor:0.75 Rotor speed: 70 rpm Banbury temperature: 30° C. Time Operation 0″add CEC masterbatch 4′ add BR bale 7′ add powders 9′ dump Sample No DumpTemperature (° C.) Energy Input (KWH) 6.1 (stage 1) 114.8 1.67 6-2(stage 1) 115.6 1.72 Stage 2: Fill factor: 0.65 Rotor speed: 70 rpmBanbury temperature: 30° C. Time Operation 0″ add stage 1 compound andcuratives 3′00″ dump Sample No Dump Temperature (° C.) Energy Input(KWH) 6-1 81.8 0.47 6-2 81.4 0.47 Mixing method 7: Stage 1: Fill factor:0.75 Rotor speed: 10 rpm Banbury temperature: 30° C. Time Operation 0″add CEC masterbatch 2′ add BR masterbatch 5′ add powders and oil 7′ dumpSample No Dump Temperature (° C.) Energy input (KWH) 7-1 (stage 1) 117.41.33 7-2 (stage 1) 112.6 1.21 7-3 (stage 1) 108.0 1.14 7-4 (stage 1)105.7 1.24 Stage 2: Fill factor: 0.65 Rotor speed: 70 rpm Banburytemperature: 30° C. Time Operation 0″ add stage 1 compound and curatives3′00″ dump Sample No Dump Temperature (° C.) Energy Input (KWH) 7-1 83.60.48 7-2 83.0 0.48 7-3 83.6 0.46 7-4 53.4 0.48 Mixing method 8: Stage 1:Fill factor: 0.75 Rotor speed: 70 rpm Banbury temperature: 30° C. TimeOperation 0″ add CEC masterbatch 2′ add BR masterbatch 5′ add powders 7′dump Sample ID Dump Temperature (° C.) Energy Input (KWH) 8-1 (stage 1)106.4 1.25 8-2 (stage 1) 112.4 1.27 8-3 (stage 1) 103.1 1.13 8-4(stage 1) 111.3 1.20 Stage 2: Fill factor: 0.65 Rotor speed: 70 rpmBanbury temperature: 3° C. Time Operation 0″ add state 1 compound andcuratives 3′00″ dump Sample ID Dump Temperature (° C.) Energy Input(KWH) 8-1 78.8 0.46 8-2 81.0 0.45 8-3 76.4 0.44 8-4 79.5 0.44

[0277] TABLE 1 Sample Description and Code for NR/BR Blends MixingSample Ratio of Black loading in Black loading in Oil loaded Method No.Description No. NR/BR natural rubber butadiene rubber to 1 blend naturalrubber masterbatch, in which 1-1 90/10 55.5 phr 0 phr blend all carbonblack was loaded, with butadiene 1-2 80/20 82.5 phr 0 phr blend rubberand oil. 1-3 70/30 71.4 phr 0 phr blend 2 blend natural rubbermasterbatch, in which all carbon 2-1 80/20 02.5 phr 0 phr natural rubberblack and oil were loaded, with butadiene rubber. 2-2 70/30 71.4 phr 0phr natural rubber 3 blend natural rubber masterbatch, in which 50 phrof 3-1 80/20 50 phr 50 phr blend carbon black was loaded, with butadienerubber 3-2 70/30 50 phr 50 phr blend masterbatch, in which 50 phr ofcarbon black was 3-3 60/40 50 phr 50 phr blend loaded, and oil. 3-450/50 50 phr 50 phr blend 4 blend natural rubber masterbatch, in which50 phr of 4-1 80/20 50 phr 50 phr natural rubber carbon block and alloil were loaded, with butadiene 4-2 70/30 50 phr 50 phr natural rubberrubber masterbatch, in which 50 phr of carbon black 4-3 60/40 50 phr 50phr natural rubber was loaded. 4-4 50/50 50 phr 50 phr natural rubber 5blend CEC masterbatch, in which 5-1 90/10 55.5 phr 0 phr blend allcarbon black was loaded, with butadiene 5-2 80/20 62.5 phr 0 phr blendrubber and oil. 5-3 70/30 71.4 phr 0 phr blend 6 blend CEC masterbatch,in which all carbon 6-1 80/20 62.5 phr 0 phr CEC black and oil wereloaded, with butadiene rubber. 6-2 70/30 71.4 phr 0 phr CEC 7 blend CECmasterbatch, in which 50 phr of 7-1 60/20 50 phr 50 phr blend carbonblack was loaded, with butadiene rubber 7-2 70/30 50 phr 50 phr blendmasterbatch, in which 50 phr of carbon black was 7-3 60/40 50 phr 50 phrblend loaded, and oil. 7-4 50/50 50 phr 50 phr blend 8 blend CECmasterbatch, in which 50 phr of 8-1 80/20 50 phr 50 phr CEC carbon blackand all oil were loaded, with butadiene 8-2 70/30 50 phr 50 phr CECrubber masterbatch, in which 50 phr of carbon black 8-3 60/40 50 phr 50phr CEC was loaded. 8-4 50/50 50 phr 50 phr CEC

[0278] TABLE 2 Compound Characterization of NR/BR Blends Mixing MooneyViscosity Undispersed Area Sol Molecular Weight Bound Rubber Method No.Sample No. ML(1 + 4) @ 100° C. % K % 1 1-1 58 1.15 298 40 1-2 60 1.00277 42 1-3 64 2.04 243 43 2 2-1 63 1.28 278 41 2-2 62 1.28 248 41 3 3-162 0.86 337 37 3-2 61 0.58 336 36 3-3 64 0.55 338 36 3-4 64 0.84 333 344 4-1 70 0.68 359 37 4-2 70 0.62 361 37 4-3 68 0.68 342 37 4-4 65 0.84324 35 5 5-1 58 334 43 5-2 58 319 43 5-3 58 296 41 6 6-1 60 0.32 430 386-2 59 0.40 347 37 7 7-1 65 0.51 422 43 7-2 65 0.46 434 42 7-3 62 0.54428 40 7-4 64 0.47 404 41 8 8-1 62 0.52 401 40 8-2 64 0.52 434 40 8.3 580.65 407 34 8-4 63 0.51 359 41

[0279] TABLE 3 Physical Properties of NR/BR Blonde E100 E300 TensileElongation Rebound Rebound Rebound Sample No. Hardness MPa MPa MPa % 60°C., % 0° C., % r.t., % 1-1 65 2.9 16 29 500 82 30 52 1-2 64 3.1 17 28462 65 43 55 1-3 65 3.2 18 25 404 85 46 50 2-1 69 2.9 16 26 459 60 39 502-2 69 2.9 16 24 434 80 41 51 3-1 65 2.4 13 28 510 63 43 53 3-2 66 2.413 26 514 63 45 54 3-3 66 2.5 13 25 488 82 48 54 3-4 67 2.5 13 23 488 8249 57 4-1 68 2.6 14 27 502 81 42 52 4-2 69 2.8 14 25 472 61 43 53 4-3 882.8 14 24 487 60 44 53 4-4 68 2.7 14 24 459 60 46 53 5-1 65 2.9 17 28452 05 41 54 5-2 84 2.8 16 27 452 00 43 66 5-3 84 2.9 16 25 432 65 45 566-1 66 2.6 14 27 505 62 42 54 6-2 65 2.9 15 28 462 63 45 55 7-1 68 3.017 29 472 64 45 55 7-2 68 3.0 17 28 459 84 48 57 7-3 67 2.9 16 25 429 6448 58 7-4 87 3.0 18 23 397 65 51 59 8-1 87 2.8 15 28 480 64 46 56 8-2 872.8 15 27 475 64 47 56 8-3 86 2.6 14 25 465 62 47 55 8-4 65 2.8 15 23400 67 64 60

[0280] TABLE 4 Fracture Properties and Dynamic Property of NR/BR BlendsCrack Growth Rate Tear Strength Max. Tan δ Sample No. ×10⁻⁵, cm/millioncycle Die C, N/mm Abrasion Rating @ 50° C. 1-1 4.32 126 81 0.178 1-23.11 68 83 0.147 1-3 1.34 54 68 0.132 2-1 4.37 55 100 0.178 2-2 2.39 5099 0.164 3-1 4.30 107 74 0.165 3-2 3.86 97 80 0.161 3-3 3.54 80 85 0.1533-4 2.23 73 100 0.158 4-1 4.47 108 85 0.188 4-2 4.04 104 96 0.173 4-33.82 70 113 0.175 4-4 3.73 63 150 0.174 5-1 4.03 78 114 0.176 5-2 3.7265 113 0.156 5.3 1.99 62 98 0.152 6-1 1.64 75 101 0.186 6-2 0.61 61 1070.166 7-1 4.59 70 117 0.178 7-2 4.30 75 132 0.166 7-3 4.81 56 144 0.1517-4 3.43 52 146 0.132 8-1 5.08 66 112 0.186 8-2 4.60 66 134 0.181 8-35.19 58 140 0.165 8-4 4.43 64 138 0.140

Mixing Procedures of CEC/RSS1 Blends and Dry Mix RSS1 Compound

[0281] Mixing Method

[0282] Dry: Masticated RSS1 was mixed with other ingredients;

[0283] CEC: Blend CEC masterbatch, in which all carbon black was loaded,with masticated RSS1 and oil. The ratios of CEC natural rubber to RSS1natural rubber were 100/0, 90/10, 80/20 and 70/30.

[0284] Mixing Procedures

[0285] A three stage Banbury mix was used for dry mix compound and twostage Banbury mix for CEC/RSS1 blends. RSS1 natural rubber wasmasticated before first stage mix for dry mix compound and CEC/RSS1blends. RSS1 mastication condition: Fill factor: 0.75 Rotor speed; 100rpm Banbury Temperature: 30° C. Total batch energy: 950 Watt-HoursBanbury mixing procedures: Dry: Stage 1: Fill factor: 0.65 Rotor speed:70 rpm Banbury temperature: 30° C. Time Operation 0″ add masticated RSS130″ add 30 phr of CB 1′00″ add ½ remaining CB 1′30″ add remaining CB 10′dump according to power curve Energy Sample Code. Mixing time Dump temp.(° C.) input (KWH) Dry (stage 1) 10′ 130 1.7 Stage 2: Fill factor: 0.70Rotor speed: 70 rpm Banbury temperature: 30° C. Time Operation 0″ addstage 1 masterbatch, oil and all chemicals except curatives 3′00″ dumpSample Code Dump Temperature (° C.) Energy Input (KWH) Dry (stage 2) 1240.42 Stage 3: Fill factor: 0.65 Rotor speed: 70 rpm Banbury temperature:30° C. Time Operation 0″ add stage 2 compound and curatives 3′00″ dumpSample Code Dump Temperature (° C.) Energy Input (KWH) 1-1 91 0.38 CEC:Stage 1: Fill factor: 0.75 Rotor speed: 70 rpm Banbury temperature: 30°C. Time Operation 0″ add CEC masterbatch 4′ add masticated RSS1 7′ addpowders and oil 6′-9′ dump Dump Temperature Sample Code (° C.) Energyinput (KWH) Mixing Time CEC-1 (stage 1) 113.9 1.28 6′ CEC-2 (stage 1)104.2 1.78 9′ CEC-3 (stage 1) 107.1 1.72 9′ CEC-4 (stage 1) 103.9 1.799′ Stage 2: Fill factor: 0.65 Rotor speed: 70 rpm Banbury temperature:30° C. Time Operation 0″ add stage 1 compound and curatives 3′00″ dumpSample No Dump Temperature (° C.) Energy input (KWH) CEC-1 81.3 0.63CEC-2 76.7 0.46 CEC-3 81.0 0.46 CEC-4 83.3 0.48

[0286] TABLE 1 Sample Description and Code for CEC/RSS1 Blends MixingSample Ratio of Black loading in Black loading in Oil loaded MethodDescription Code CEC/RSS1 CEC RSS1 to Dry natural rubber (RSS1) wasmixed with ingredients Dry / / 50 phr dry CEC blend CEC masterbatch, inwhich CEC-1 100/0    50 phr / CEC all carbon black was loaded, withmasticated CEC-2 90/10 55.5 phr  0 phr blend RSS1 and oil. CEC-3 80/2062.5 phr  0 phr blend CEC-4 70/30 71.4 phr  0 phr blend

[0287] TABLE 2 Compound Characteristics of CEC/RSS1 Blends Sample MooneyViscosity Sol Molecular Weight Bound Rubber Code ML(1 + 4) @ 100° C. K %Dry 61 304 38 CEC-1 63 378 41 CEC-2 61 362 46 CEC-3 61 363 48 CEC-4 60377 45

[0288] TABLE 3 Physical Properties of CEC/RSS1 Blends E100 E300 TensileElongation Rebound Rebound Rebound Sample No. Hardness MPa MPa MPa % 60°C., % 0° C., % r.t., % Dry 69 2.8 15 27 472 59 35 48 CEC-1 89 2.7 15 30533 82 30 50 CEC-2 88 3.0 17 30 483 83 39 52 CEC-3 63 2.8 17 30 497 8438 53 CEC-4 85 2.8 18 31 506 85 38 54

[0289] TABLE 4 Fracture Properties and Dynamic Property of CEC/RSS1Blends Crack Growth Sample Rate ×10⁻⁵, Tear Strength Abrasion Max. Tan δCode cm/million cycle Die C, N/mm Rating @ 60° C. Dry 4.83 122   800.178 CEC-1 3.43 91 120 0.179 CEC-2 4.31 94 110 0.174 CEC-3 3.65 97 1060.174 CEC-4 4.11 106   98 0.168

[0290] In view of the foregoing disclosure, it will be apparent to thoseskilled in the art that various additions, modifications, etc. can bemade without departing from the true scope and spirit of the invention.All such additions and modifications are intended to be covered by thefollowing claims.

We claim:
 1. A method of producing elastomer composite blend,comprising: feeding a continuous flow of first fluid comprisingelastomer latex to a mixing zone of a coagulum reactor; feeding acontinuous flow of second fluid comprising particulate filler underpressure to the mixing zone of the coagulum reactor to form a mixturewith the elastomer latex, the particulate filler being effective tocoagulate the elastomer latex and the mixing of the first fluid and thesecond fluid within the mixing zone being sufficiently energetic tosubstantially completely coagulate the elastomer latex with theparticulate filler in the coagulum reactor; discharging a substantiallycontinuous flow of elastomer composite from the coagulum reactor; anddry mixing the elastomer composite with additional elastomer to formelastomer composite blend.
 2. The method of producing elastomercomposite blend in accordance with claim 1 wherein the elastomer latexcomprises elastomer selected from natural rubber, chlorinated naturalrubber, homopolymer, copolymer terpolymers of 1,3-butadiene, styrene,isoprene, isobutylene, 2,3-dimethyl-1,3-butadiene, acrylonitrile,ethylene, and propylene, the oil extended derivatives of any of them,and mixtures of any of them.
 3. The method of producing elastomercomposite blend in accordance with claim 1 wherein the elastomer latexcomprises elastomer selected from natural rubber, BR, SBR, and mixturesof any of them.
 4. The method of producing elastomer composite blend inaccordance with claim 1 wherein the additional latex is natural rubber,chlorinated natural rubber, homopolymer, copolymer or terpolymer of1,3-butadiene, styrene, isoprene, isobutylene,2,3-dimethyl-1,3-butadiene, acrylonitrile, ethylene, and propylene, theoil extended derivative of any of them, or a mixture of any of them. 5.The method of producing elastomer composite blend in accordance withclaim 1 wherein the additional latex is natural rubber, BR, SBR or amixture of any of them.
 6. The method of producing elastomer compositeblend in accordance with claim 1 wherein the elastomer latex comprises afirst elastomer, and the additional elastomer is the same as the firstelastomer.
 7. The method of producing elastomer composite blend inaccordance with claim 1 wherein the elastomer, latex comprises a firstelastomer, and the additional elastomer comprises a second elastomerdifferent from the first elastomer.
 8. The method of producing elastomercomposite blend in accordance with claim 1 wherein the particulatefiller is selected from carbon black, fumed silica, precipitated silica,coated carbon blacks, chemically functionalized carbon blacks,silicon-treated carbon black, and mixtures of any of them.
 9. The methodof producing elastomer composite blend in accordance with claim 1wherein the particulate filler is carbon black.
 10. The method ofproducing elastomer composite blend in accordance with claim 1 whereinthe particulate filler is silica.
 11. The method of producing elastomercomposite blend in accordance with claim 1 wherein the elastomercomposite blend has 30 to 85 phr of the particulate filler.
 12. Themethod of producing elastomer composite blend in accordance with claim 1wherein additional particulate filler is added during the dry mixing ofthe elastomer composite with additional elastomer.
 13. The method ofproducing elastomer composite blend in accordance with claim 12 whereinthe additional particulate filler is the same as the particulate fillerof the second fluid.
 14. The method of producing elastomer compositeblend in accordance with claim 12 wherein the additional particulatefiller is carbon black, fumed silica, precipitated silica, coated carbonblacks, chemically functionalized carbon blacks, silicon-treated carbonblack, and any mixture of them.
 15. The method of producing elastomercomposite blend in accordance with claim 11 wherein the additionalparticulate filler is carbon black.
 16. The method of producingelastomer composite blend in accordance with claim 11 wherein theadditional particulate filler is silica.
 17. The method of producingelastomer composite blend in accordance with claim 12 wherein theparticulate filler the elastomer composite blend has the particulatefiller of 30 to 85 phr.
 18. The method of producing elastomer compositeblend in accordance with claim 1 further comprising feeding additive tothe mixing zone of the coagulum reactor.
 19. The method of producingelastomer composite blend in accordance with claim 18 wherein theadditive is selected from antiozonants, antioxidants, plasticizers,processing aids, resins, flame retardants, extender oils, lubricants,and mixtures of any of them.
 20. The method of producing elastomercomposite blend in accordance with claim 1 further comprising addingadditive during dry mixing of the elastomer composite with additionalelastomer.
 21. The method of producing elastomer composite blend inaccordance with claim 20 wherein the additive is selected fromantiozonants, antioxidants, plasticizers, processing aids, resins, flameretardants, extender oils, lubricants, and mixtures of any of them. 22.The method of producing elastomer composite blend in accordance withclaim 1 wherein the weight ratio in the elastomer composite blend ofelastomer in the elastomer composite blend from the elastomer latex tothe additional elastomer is from 95:5 to 5:95.
 23. The method ofproducing elastomer composite blend in accordance with claim 1 whereinthe elastomer latex is natural rubber latex and the additional elastomeris butadiene rubber, and butadiene rubber is from 10% to 50% by weightof total elastomer in the elastomer composite blend.
 24. The method ofproducing elastomer composite blend in accordance with claim 1 whereinthe elastomer latex is natural rubber latex and the additional elastomeris SBR, and SBR is from 50% to 90% by weight of total elastomer in theelastomer composite blend.
 25. The method of producing elastomercomposite blend in accordance with claim 1 wherein the elastomer latexis natural rubber latex and the additional elastomer is natural rubber.26. The method of producing elastomer composite blend in accordance withclaim 1 wherein the elastomer latex is butadiene rubber latex and theadditional elastomer is SBR, and SBR is from 10% to 90% by weight oftotal elastomer in the elastomer composite blend.
 27. The method ofproducing elastomer composite blend in accordance with claim 1 whereinthe elastomer latex is butadiene rubber latex and the additionalelastomer is butadiene rubber.
 28. The method of producing elastomercomposite blend in accordance with claim 1 wherein the elastomer latexis butadiene rubber latex and the additional elastomer is naturalrubber, and natural rubber is from 10% to 50% by weight of totalelastomer in the elastomer composite blend.
 29. The method of producingelastomer composite blend in accordance with claim 1 wherein theelastomer latex is SBR latex and the additional elastomer is butadienerubber, and butadiene rubber is from 10% to 90% by weight of totalelastomer in the elastomer composite blend.
 30. The method of producingelastomer composite blend in accordance with claim 1 wherein theelastomer latex is latex SBR and the additional elastomer is SBR. 31.The method of producing elastomer composite blend in accordance withclaim 1 wherein the elastomer latex is SBR and the additional elastomeris natural rubber, and natural rubber is from 50% to 90% by weight oftotal elastomer in the elastomer composite blend.
 32. The method inaccordance with any of claims 23 to 31 wherein the elastomer compositeblend has 30 to 85 phr carbon black.
 33. The method of producingelastomer composite blend in accordance with claim 1 wherein thecoagulum reactor defines an elongate coagulum zone extending from themixing zone to a discharge end.
 34. Elastomer composite blend comprisingparticulate filler finely dispersed in elastomer, formed by a methodcomprising the steps of: A) establishing a continuous, semi-confinedflow of mixed elastomer latex and particulate filler under pressure in acoagulum reactor forming an elongate coagulum zone extending withprogressively increasing cross-sectional area from an entry end to adischarge end, by simultaneously (i) feeding elastomer latex fluidcontinuously to a mixing zone at the entry end of the coagulum reactor,and (ii) entraining the elastomer latex fluid into particulate fillerfluid by feeding the particulate filler fluid as a continuous jet intothe mixing zone; B) discharging from the discharge end of the coagulumreactor a substantially constant flow of elastomer masterbatch globulesconcurrently with feeding of the fluid streams in accordance with stepsA(i) and A(ii); and C) dry mixing the elastomer composite withadditional elastomer to form elastomer composite blend.
 35. Elastomercomposite blend formed by: feeding a continuous flow of first fluidcomprising elastomer latex to a mixing zone of a coagulum reactor;feeding a continuous flow of second fluid comprising particulate fillerunder pressure to the mixing zone of the coagulum reactor to form amixture with the elastomer latex, the particulate filler being effectiveto coagulate the elastomer latex, the particulate filler being effectiveto coagulate the elastomer latex and the mixing of the first fluid andthe second fluid within the mixing zone being sufficiently energetic tosubstantially completely coagulate the elastomer latex with theparticulate filler in the coagulum reactor; discharging a substantiallycontinuous flow of elastomer composite from the coagulum reactor; anddry mixing the elastomer composite with additional elastomer to formelastomer composite blend.
 36. The elastomer composite blend of claim 34or 35 wherein macro-dispersion D(%) of the particulate filler in a firstelastomer phase of the elastomer composite blend comprising essentiallyelastomer from the elastomer latex is less than 0.2% undispersed area.37. The elastomer composite blend of claim 34 or 35 whereinmacro-dispersion D(%) of the particulate filler throughout the elastomercomposite blend is less than 0.2% undispersed area.
 38. The elastomercomposite blend of claim 35 wherein the particulate filler is carbonblack, silicon coated carbon black, silicon treated carbon black, fumedsilica, precipitated silica or a mixture of any of them.
 39. Theelastomer composite blend of claim 35 wherein the elastomer of theelastomer latex is selected from natural rubber, a chlorinatedderivative of natural rubber, a homopolymer, copolymer or terpolymer ofbutadiene, styrene, isoprene, isobutylene, 3,3-dimethyl-1,3-butadiene,acrylonitrile, ethylene propylene, an oil extended derivative of any ofthem and a mixture of any of them.
 40. An elastomer composite blendcomprising at least 30 phr particulate filler dispersed in a multi-phaseelastomer, the particulate filler being selected from carbon black,silicon coated carbon black, silicon treated carbon black, fumed silica,precipitated silica or a mixture of any of them, and each phase of themultiphase elastomer being independently selected from natural rubber, achlorinated derivative of natural rubber, homopolymer, copolymer orterpolymer of butadiene, styrene, isoprene, isobutylene,3,3-dialkyl-1,3-butadiene where the alkyl group is C1 to C3 alkyl,acrylonitrile, ethylene and propylene, an oil extended derivative of anyof them and a mixture of any of them wherein macro-dispersion D(%) ofthe particulate filler in the elastomer composite blend is less than0.2% undispersed area.
 41. Vulcanizate comprising the vulcanizationproduct of elastomer composite blend in accordance with any of claims33, 34 or
 39. 42. Tire tread comprising vulcanizate in accordance withclaim
 41. 43. Tire sub-tread comprising vulcanizate in accordance withclaim
 41. 44. Wire-skim for a tire comprising vulcanizate in accordancewith claim
 41. 45. Tire sidewall comprising vulcanizate in accordancewith claim
 41. 46. Cushion gum for a re-tread tire, comprisingvulcanizate in accordance with claim
 41. 47. A rubber component of anengine mount, comprising vulcanizate in accordance with claim
 41. 48.Tank track comprising vulcanizate in accordance with claim
 41. 49.Mining belt, comprising vulcanizate in accordance with claim
 41. 50. Arubber component of a hydro-mount comprising vulcanizate in accordancewith claim
 41. 51. A bridge bearing comprising vulcanizate in accordancewith claim
 41. 52. A seismic isolator comprising vulcanizate inaccordance with claim
 41. 53. Vulcanizate in accordance with any ofclaims 41 having a crack growth rate no more than 1.20 cm/millioncycles, measured in accordance with ASTM D3629-94.